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josmiceli answered: 9661 problems
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Circles/297798: I am having trouble in my college geometry class. The problem is as follows:
Find the circumference and area of the circle whose equation is x^2 + y^2 =36. Round to the nearest tenth.
1 solutions

Answer 214393 by josmiceli(9664) About Me  on 2010-04-28 13:30:13 (Show Source):
You can put this solution on YOUR website!
x%5E2+%2B+y%5E2+=+36
When x+=+0,
y+=+6 and
y+=+-6
also
When y+=+0
x+=+6 and
x+=+-6
So, the diameter is 6+-+%28-6%29+=+12
measured along either axis, and the radius is
12%2F2+=+6
Just plug this into
A+=+pi%2Ar%5E2
and C+=+2%2Api%2Ar




Quadratic_Equations/297403: I am having trouble with writing in 50 words why the line x=4 is a vertical line. I think that x=4 is a vrtical line because it is perpindicular to the y axis.Can you help me please? I would very much appreciate it.
1 solutions

Answer 214204 by josmiceli(9664) About Me  on 2010-04-27 19:16:19 (Show Source):
You can put this solution on YOUR website!
The thing to think about is this: No matter what this line
looks like you know that every point imaginable on the line
must satisfy it's equation which is x+=+4 whatever
y ends up being. The line is perpendicular to the x axis
at x+=+4.


Age_Word_Problems/297444: Hot chocolate sells for $.75 and coffee sells for $.50 at a football game. If they sold $200 worth of hot drinks and used 295 cups, how many of each drink did they sell?
1 solutions

Answer 214201 by josmiceli(9664) About Me  on 2010-04-27 19:10:27 (Show Source):
You can put this solution on YOUR website!
Let h = number of hot chocolates sold
Let c = number of coffees sold
given:
(1) h+%2B+c+=+295
(2) .75h+%2B+.5c+=+200
Multiply both sides of (1) by .5
and subtract from (2)
.75h+%2B+.5c+=+200
-+.5h+-+.5c+=+-+147.5
.25h+=+52.5
h+=+210
and, since
h+%2B+c+=+295
c+=+295+-+210
c+=+85
They sold 210 hot chocolates and 85 coffees
check:
(2) .75h+%2B+.5c+=+200
(2) .75%2A210+%2B+.5%2A85+=+200
157.5+%2B+42.5+=+200
200+=+200
OK



Rational-functions/297439: After taking 3 quizzes, your average is 79 out of 100. What must your average score be on the next five quizzes to increase your average to 84?
1 solutions

Answer 214195 by josmiceli(9664) About Me  on 2010-04-27 19:00:59 (Show Source):
You can put this solution on YOUR website!
Let x = the sum of the first 3 quiz scores
given:
x%2F3+=+.79
x+=+2.37
Let y = the sum of the last 5 quiz scores
%282.37+%2B+y%29%2F%285+%2B+3%29+=+.84
2.37+%2B+y+=+.84%2A8
y+=+6.72+-+2.37
y+=+4.35
4.35%2F5+=+.87
The average score of the last 5 quizes is 87%


Proportions/297433: a student answered 87.5% of the exam correctly. if she answered 42 problems correctly, how many questions were therer on the exam?
1 solutions

Answer 214189 by josmiceli(9664) About Me  on 2010-04-27 18:50:36 (Show Source):
You can put this solution on YOUR website!
Let x = number of questions on exam
42%2Fx+=+.875
.875x+=+42
x+=+42%2F.875
x+=+48
There were 48 questions on the exam


Polynomials-and-rational-expressions/297418: A number minus twice its reciprocal is the same as the reciprocal of four times the number. find the number.
I have the equation as x-2 1/x = 1/4x
then i multiplied 2 by 1/x and got 2/x
Then i changed the x/1-2/x into the same base so we can subtract and got (x^2-2)/x + 1/4x
From there i am lost.
1 solutions

Answer 214184 by josmiceli(9664) About Me  on 2010-04-27 18:39:47 (Show Source):
You can put this solution on YOUR website!
Let n= the number
n+-+2%2A%281%2Fn%29+=+1%2F%284n%29
Multiply both sides by n
n%5E2+-+2+=+1%2F4
Multiply both sides by 4
4n%5E2+-+8+=+1
4n%5E2+=+9
n%5E2+=+9%2F4
Take the square root of both sides
n+=+3%2F2
and
n+=+-3%2F2
check answer:
n+-+2%2A%281%2Fn%29+=+1%2F%284n%29
%28-3%2F2%29+-+2%2A%281%2F%28-3%2F2%29%29+=+1%2F%284%2A%28-3%2F2%29%29
Multiply both sides by 2
-3+-+4%2A%28-2%2F3%29+=+-1%2F3
-3+%2B+8%2F3+=+-1%2F3
-9%2F3+%2B+8%2F3+=+-1%2F3
-1%2F3+=+-1%2F3
OK


Linear-equations/297417: How to you solve :
2x + 4y=8
1 solutions

Answer 214182 by josmiceli(9664) About Me  on 2010-04-27 18:29:38 (Show Source):
You can put this solution on YOUR website!
You can't solve this. Solving means to find the
numerical values of the unknowns, x and y
In order to solve, the number of unknowns must
equal the number of equations. You have 2 unknowns
and only 1 equation.
You can make an x-y plot of the equation. It's a
straight line and here it is:
+graph%28+500%2C+500%2C+-10%2C+10%2C+-10%2C+10%2C+-%281%2F2%29%2Ax+%2B+2%29+


Systems-of-equations/297277: Sammy sold 700 tickets totaling $13330. If the tickets were $25 adi;ts amd $15 students, how many of each ticket did Sammy sell?

1 solutions

Answer 214087 by josmiceli(9664) About Me  on 2010-04-27 14:05:40 (Show Source):
You can put this solution on YOUR website!
Let a = number of adult tickets sold
Let s = number of student tickets sold
given:
(1) a+%2B+s+=+700
(2) 25a+%2B+15s+=+13330
-----------------------
Multiply both sides of (1) by 15 and
subtract from (2)
25a+%2B+15s+=+13330
-15a+-+15s+=+-10500
10a+=+2830
a+=+283
and, since
a+%2B+s+=+700
s+=+700+-+283
s+=+417
Sammy sold 283 adult and 417 student tickets
check:
25%2A283+%2B+15%2A417+=+13330
7075+%2B+6255+=+13330
13330+=+13330
OK


Expressions-with-variables/297269: Tom can do a job in 4 hours, Joy can do the same job in 3 hours, How many hours will it take the two of them to do the job if they work together
1 solutions

Answer 214081 by josmiceli(9664) About Me  on 2010-04-27 13:56:55 (Show Source):
You can put this solution on YOUR website!
Add their rates of working to get their
rate working together
Tom's rate: (1 job)/(4 hrs)
Joy's rate: (1 job)/(3 hrs)
1%2F4+%2B+1%2F3+=+1%2Fx
Multiply both sides by 12x
3x+%2B+4x+=+12
7x+=+12
x+=+12%2F7 hrs


logarithm/297262: log(3,1/81)
1 solutions

Answer 214080 by josmiceli(9664) About Me  on 2010-04-27 13:51:02 (Show Source):
You can put this solution on YOUR website!
log%283%2C%281%2F81%29%29
Let this expression equal x
x+=+log%283%2C%281%2F81%29%29
Rewrite this as:
3%5Ex+=+1%2F81
3%5Ex+=+1%2F%283%5E3%29
3%5Ex+=+3%5E%28-3%29
x+=+-3
log%283%2C%281%2F81%29%29+=+-3


Finance/297266: What are the algebraic formulas for this (in a collection of nickels, dimes, and quarters, there are twice as many dimes as nickels and 3 fewer quarters than dimes. if the total value is $4.50 how many of each coin are there)
1 solutions

Answer 214077 by josmiceli(9664) About Me  on 2010-04-27 13:43:33 (Show Source):
You can put this solution on YOUR website!
Let n = number of nickels
Let d = number of dimes
Let q = number of quarters
given:
d+=+2n
q+=+d+-+3
5n+%2B+10d+%2B+25q+=+450 (in cents)
--------------------------
This is 3 equations and 3 unknowns, so it's solvable
By substitutions:
5n+%2B+10d+%2B+25%2A%28d+-+3%29+=+450
And, substituting again:
5%2A%28d%2F2%29+%2B+10d+%2B+25%2A%28d+-+3%29+=+450
5d%2F2+%2B+10d+%2B+25d+-+75+=+450
5d+%2B+20d+%2B+50d+-+150+=+900
75d+=+1050
d+=+14
and, since
q+=+d+-+3
q+=+11
and
n+=+d%2F2
n+=+7
There are 14 dimes, 11 quarters, and 7 nickels
check:
5n+%2B+10d+%2B+25q+=+450
5%2A7+%2B+10%2A14+%2B+25%2A11+=+450
35+%2B+140+%2B+275+=+450
450+=+450
OK


Travel_Word_Problems/297242: If i ride my bike 8 miles and then walk 4 miles it takes me 3hrs. If i walk 1/4 the rate that i ride, how fast did i ride my bike?
1 solutions

Answer 214073 by josmiceli(9664) About Me  on 2010-04-27 13:27:35 (Show Source):
You can put this solution on YOUR website!
Let b = your speed riding your bike
Then, your speed walking is %281%2F4%29%2Ab
In words:
(time spent walking and biking) = (distance biking/biking speed) + (distance walking/walking speed)
3+=+8%2Fb+%2B+4%2F%28%281%2F4%29%2Ab%29
Multiply both sides by %281%2F4%29%2Ab
%283%2F4%29%2Ab+=+2+%2B+4
3b+=+4%2A6
b+=+8
The speed biking is 8 mi/hr
check:
3+=+8%2Fb+%2B+4%2F%28%281%2F4%29%2Ab%29
3+=+8%2F8+%2B+4%2F%28%281%2F4%29%2A8%29
3+=+1+%2B+4%2F2
3+=+3
OK


Linear_Equations_And_Systems_Word_Problems/297255: 8.25 months = how many days
1 solutions

Answer 214059 by josmiceli(9664) About Me  on 2010-04-27 13:17:00 (Show Source):
You can put this solution on YOUR website!
This is a problem of converting units.
First of all, forget about any numbers.
Just write an expression with units only.
Units are hours, yards, dollars, days, miles/hours, etc.
In this problem,
(months)*(days/month) = days
All months don't have 30 days, but it's a common estimate
Now write it with numbers:
8.25 months x 30 days/month = 247.5 days


Travel_Word_Problems/297107: A dog is walking along a train track on e day, and traceled along that track onto a train bridge. When the dog was 1/4 of the way across the bridge, he heard a train whistle from an oncoming train that was coming in the same direction the dog had already come. The dog bounded away form the train, and made it to the end of the bridge at exactly the same time as the train. What the dog didn't know, but what was also true, was that the dog could have bounded toward th train and made it to the "start" of the bridge at exactly the same time as the traing. The train was traceling at a speed of 30 mph. How fast was the dog traveling?
1 solutions

Answer 213973 by josmiceli(9664) About Me  on 2010-04-27 03:36:04 (Show Source):
You can put this solution on YOUR website!
Let d = the dog's speed running
Let t = the time for the train to just reach the bridge
Let b = the length of the bridge in miles
-------------------------
In words:
(dog's speed) x (time for train to reach bridge + time for train to cross bridge) = (3/4)x(the length of the bridge)
As an equation:
(1) d%2A%28t+%2B+b%2F30%29+=+%283%2F4%29%2Ab
---------------------------
In words:
(dog's speed) x (time for train to reach bridge) = (1/4)*(length of bridge)
As an equation:
(2) d%2At+=+%281%2F4%29%2Ab
---------------------------
In words:
(train's speed plus dog's speed) x (time for train to reach bridge) = (distance train travels to reach bridge plus distance dog runs)
As an equation:
(3) %2830+%2B+d%29%2At+=+30t+%2B+%281%2F4%29%2Ab
----------------------------
This is 3 equations and 3 unknowns, so it's solvable
(1) d%2A%28t+%2B+b%2F30%29+=+%283%2F4%29%2Ab
(1) dt+%2B+db%2F30+=+%283%2F4%29%2Ab
(1) 60dt+%2B+2db+=+45b
and
(2) dt+=+%281%2F4%29%2Ab
and
(3) %2830+%2B+d%29%2At+=+30t+%2B+%281%2F4%29%2Ab
(3) 30t+%2B+dt+=+30t+%2B+%281%2F4%29%2Ab
(3) 120t+%2B+4%2Adt+=+120t+%2B+b
I can substitute (2) in (1)
(1) 60%2A%281%2F4%29%2Ab+%2B+2db+=+45b
(1) 15b+%2B+2db+=+45b
(1) 2db+=+30b
(1) d+=+15
The dog was running 15 mi/hr
check answer:
(2) dt+=+%281%2F4%29%2Ab
(2) 15t+=+%281%2F4%29%2Ab
(2) b+=+60t
Substitute in (3)
(3) 120t+%2B+4%2Adt+=+120t+%2B+b
(3) 120t+%2B+4%2A15%2At+=+120t+%2B+60t
(3) 120t+%2B+60t+=+120t+%2B+60t
OK




Finance/297117: how many liters of 40% solution has to be added to 10 leiters of 80% to make 60%?
I need linier equations with 2 viariables to solve
1 solutions

Answer 213970 by josmiceli(9664) About Me  on 2010-04-27 02:25:06 (Show Source):
You can put this solution on YOUR website!
Let x = liters of 40% solution needed
Let y = liters of 60% solution you end up with
given:
(1) y+=+x+%2B+10
(2) %28.4x+%2B+.8%2A10%29%2Fy+=+.6
-------------------------------------
from (2),
(2) .4x+%2B+.8%2A10+=+.6y
6y+=+4x+%2B+80
-----------------------
y+=+%282%2F3%29%2Ax+%2B+40%2F3
and
y+=+x+%2B+10 answers
--------------------------
check answers:
%282%2F3%29%2Ax+%2B+40%2F3+=+x+%2B+10
2x+%2B+40+=+3x+%2B+30
x+=+10
and, since
y+=+x+%2B+10
y+=+20
(2) %28.4x+%2B+.8%2A10%29%2Fy+=+.6
(2) %28.4%2A10+%2B+.8%2A10%29%2F20+=+.6
%284+%2B+8%29%2F20+=+.6
12%2F20+=+.6
12+=+12
OK



Problems-with-consecutive-odd-even-integers/297121: One-fifth of sum of two consecutive integers is 22 less than the smaller integer.
Find the smaller of the two integers.
1 solutions

Answer 213967 by josmiceli(9664) About Me  on 2010-04-27 02:06:15 (Show Source):
You can put this solution on YOUR website!
Call the consecutive integers n and n%2B1
given:
%281%2F5%29%2A%28n+%2B+n+%2B+1%29+=+n+-+22
Multiply both sides by 5
2n+%2B+1+=+5%2A%28n+-+22%29
2n+%2B+1+=+5n+-+110
3n+=+111
n+=+37 answer
check:
%281%2F5%29%2A%28n+%2B+n+%2B+1%29+=+n+-+22
%281%2F5%29%2A%2874+%2B+1%29+=+37+-+22
75%2F5+=+15
75+=+75
OK


Travel_Word_Problems/296684: A jet fighter cruises at 1.5 times the speed of sound. The speed of sound is 1.24x10^3 km/hr. How many hours does it take for the jet to fly the 5.8x10^3 from new york to paris. Demonstrate the use of scientific method.
1 solutions

Answer 213755 by josmiceli(9664) About Me  on 2010-04-26 11:59:21 (Show Source):
You can put this solution on YOUR website!
The speed of the jet is
1.5%2A1.24%2A10%5E3+=+1.86%2A10%5E3 km/hr
d+=+r%2At
t+=+d%2Fr
t+=+5.8%2A10%5E3%2F%281.86%2A10%5E3%29
t+=+3.118 hr
or, about 3 hrs and 7 min


Travel_Word_Problems/296377: Two trains are coming at each other at sixty miles an hour, one from Chicago, one from Los Angeles. Given an East South East wind of 15 mph in Eastern Colorado, which train uses more fuel to reach its destination?
1 solutions

Answer 213580 by josmiceli(9664) About Me  on 2010-04-25 17:59:31 (Show Source):
You can put this solution on YOUR website!
I'm guessing a little, but I believe the wind is OUT OF
the ESE direction, so the train from Chicago will have a tailwind
(helping), and the train from LA will have a headwind (slowing it)
So, the train from Chicago should use less fuel.
(assuming they both have the same, or nearly the same, fuel efficiency)


Travel_Word_Problems/296366: The average speed of a plane is 480 kilometers per hour. How long does it take the plane to travel 140?
1 solutions

Answer 213578 by josmiceli(9664) About Me  on 2010-04-25 17:52:50 (Show Source):
You can put this solution on YOUR website!
d+=+r%2At
140+=+480%2At
t+=+140%2F480
t+=+7%2F24 hr
In minutes this is:
t+=+%287%2F24%29%2A60 min
t+=+17.5 min


Functions/296402: The gas mileage, m, of a specific car is a linear function of the speed, s, at which the car is driven,for 60 less that or equal to s less than or equal to 30. if the car is driven at a rate of 30MPH, the cars gas mileage is 35MPG. If the car is driven at 60MPH the cars gas mileage is 20MPG. I need to use this data (s,m) to write an equation for the gas mileage m. I have know idea how to do this!
1 solutions

Answer 213576 by josmiceli(9664) About Me  on 2010-04-25 17:47:28 (Show Source):
You can put this solution on YOUR website!
You need to plot this the same way you plot y+=+f%28x%29
Plot gas milage, (m) on the vertical axis and
speed, (s) on the horizontal axis. This is m+=+f%28s%29.
You are told that it's a straight line between s+=+30
and s+=+60.
Essentially what you are given is two points, (s,m) on this line
(30,35) and
(60,20)
Now you need the point-slope formula which looks like:
%28m+-+35%29%2F%28s+-+30%29+=+%2820+-+35%29%2F%2860+-+30%29
%28m+-+35%29%2F%28s+-+30%29+=+-15%2F30
Multiply both sides by s+-+30
m+-+35+=+%28-1%2F2%29%2A%28s+-+30%29
m+-+35+=+%28-1%2F2%29%2As+%2B+15
m+=+%28-1%2F2%29%2As+%2B+50
This is gas milage as a function of speed
Here's a plot:
+graph%28+500%2C+500%2C+-15%2C+110%2C+-15%2C+60%2C+%28-1%2F2%29%2Ax+%2B+50%29+
Remember that the plot is only good between s+=+30 and s+=+60


Finance/296384: FIND THE VERTEX THE LINE OF SYMMETRY THE MAXIMUM OR MINIMUM VALUES OF THE QUADRATIC FUNCTION F(X)=-X^2+10X+5

1 solutions

Answer 213568 by josmiceli(9664) About Me  on 2010-04-25 17:22:32 (Show Source):
You can put this solution on YOUR website!
f%28x%29+=+-x%5E2+%2B+10x+%2B+5
When the sign of the squared term is minus, the
curve has a max and not a min.
The x co-ordinate of the max is always at
-b%2F2a
-b+=+-10
2a+=+-2
-10%2F%28-2%29+=+5
Now I need f%285%29
f%285%29+=+-5%5E2+%2B+10%2A5+%2B+5
f%285%29+=+-25+%2B+50+%2B+5
f%285%29+=+30 maximum
The line of symmetry is simply the x-value x+=+5
Here's a plot:
+graph%28+400%2C+400%2C+-5%2C+12%2C+-5%2C+35%2C+-x%5E2+%2B+10x+%2B+5%29+


Radicals/296388: Please help me solve this radical equation. Thank you.
+%28x-4%29%5E%283%2F2%29+=-6+
1 solutions

Answer 213565 by josmiceli(9664) About Me  on 2010-04-25 17:10:13 (Show Source):
You can put this solution on YOUR website!
+%28x-4%29%5E%283%2F2%29+=+-6+
This is the same as:
%28%28x-4%29%5E%281%2F2%29%29%5E3+=+-6
Take the cube root of both sides
%28x-4%29%5E%281%2F2%29+=+%28-6%29%5E%281%2F3%29
square both sides
x+-+4+=+%28-6%29%5E%282%2F3%29
x+=+%28-6%29%5E%282%2F3%29+%2B+4
x+=+-3.302+%2B+4
x+=+.698 answer
check:
+%28x-4%29%5E%283%2F2%29+=+-6+
+%28.698+-+4%29%5E%283%2F2%29+=+-6+
+%28-3.302%29%5E%283%2F2%29+=+-6
+-6.0002+=+-6
close enough


Triangles/296392: what would the missing side be to a right triangle with the sides of 15 and 9?
1 solutions

Answer 213564 by josmiceli(9664) About Me  on 2010-04-25 16:55:10 (Show Source):
You can put this solution on YOUR website!
The missing side is either a leg or the
hypotenuse.
If it is a leg, then:
15%5E2++=+9%5E2+%2B+b%5E2
b%5E2+=+15%5E2+-+9%5E2
b%5E2+=+225+-+81
b%5E2+=+144
b+=+sqrt%28144%29
b+=+12
The missing side is a leg, and it equals 12


Geometry_Word_Problems/293223: The perimeter of a rectangle is 60 feet. Describe the possible lengths of a side if the area of the rectangle is not to exceed 144 square feet.
1 solutions

Answer 211679 by josmiceli(9664) About Me  on 2010-04-17 12:57:31 (Show Source):
You can put this solution on YOUR website!
Let the width = x
Let the length = y
Let the perimeter = P
Let the area = A
P+=+60
60+=+2x+%2B+2y
2y+=+60+-+2x
y+=+30+-+x
A+=+x%2A%2830+-+x%29
A+=+-x%5E2+%2B+30x
It is given that A+%3C=144 ft2
144+=+-x%5E2+%2B+30x
144+=+x%2A%28-x+%2B+30%29
I'll take a guess x+=+10
144+=+10%2A%28-10+%2B+30%29
144+=+200
I'll try x+=+8
144+=+8%2A%28-8+%2B+30%29
144+=+8%2A22
144+=+176
I'll try x+=+6
144+=+6%2A%28-6+%2B+30%29
144+=+6%2A24
144+=+144 OK
Next,
x+=+4
144+=+4%2A%28-4+%2B+30%29
144+=+104
I deduce that x+%3C=6
and
y+%3E=+24
Either side must be less than or equal to 6
or greater than or equal to 24









Geometry_Word_Problems/293198: A circle of radius 2 rolls completely around the inside perimeter of a square of side 10. what distance is covered by the centre of the circle ?
a 16 b 24 c 32 d 40
1 solutions

Answer 211675 by josmiceli(9664) About Me  on 2010-04-17 12:32:51 (Show Source):
You can put this solution on YOUR website!
It will trace out a square who's sides
are 1 radius away from the outside square
The outside square's sides are 10 units
apart. The inside square's sides are 2r
smaller, so 10+-+2r+=+10+-+4
10+-+4+=+6
The perimeter of a square with sides = 6 is
4%2A6+=+24 units
The answer is (b)



logarithm/293221: CAN YOU PLS TELL ME HOW TO SOLVE LOG 0.3 to the base 9..??
The answer should be 1/2.

1 solutions

Answer 211674 by josmiceli(9664) About Me  on 2010-04-17 12:23:08 (Show Source):
You can put this solution on YOUR website!
The main thing to remember is: LOGS ARE EXPONENTS
The other main thing is:
You have to know how to read this:
y+=+log%289%2C.3%29
First of all, it's telling you that y is an exponent,
since it says "y = log(something)"
Then it tells you that when you raise the base 9 to
the exponent y, the result is .3
Putting all that together:
y+=+9%5E.3
You can also express 9 as 3%5E2
y+=+%283%5E2%29%5E.3
The rule for this is to multiply the exponents
y+=+3%5E.6
You can solve this on a calculator, or
take the log to the base 10 of both sides
log%28y%29+=+.6%2Alog%283%29
log%28y%29+=+.6%2A.477
log%28y%29+=+.286
y+=+10%5E.286+
y+=+1.933
-----------------
Actually,
1%2F2+=+log%289%2C3%29
and, as I showed,
1.933+=+log%289%2C.3%29


Linear-equations/293220: Find and equation of the line containing the given pair of points (-4,0) and (0,1)
1 solutions

Answer 211673 by josmiceli(9664) About Me  on 2010-04-17 12:01:05 (Show Source):
You can put this solution on YOUR website!
The formula to use is

where
x%5B1%5D,y%5B1%5D = (-4,0) and
x%5B2%5D,y%5B2%5D = (0,1)
Plugging these values into the formula:

%28y+-+1%29%2F%28x+-+0%29+=+%280+-+1%29%2F%28-4+-+0%29
%28y+-+1%29%2Fx+=+%28-1%29%2F%28-4%29
%28y+-+1%29%2Fx+=+1%2F4
Multiply both sides by 4x
4y+-+4+=+x
4y+=+x+%2B+4
y+=+%281%2F4%29%2Ax+%2B+1 answer
check:
does it pass through the given points?
(-4,0)
0+=+%281%2F4%29%2A%28-4%29+%2B+1
0+=+-1+%2B+1
0+=+0
and
(0,1)
1+=+%281%2F4%29%2A0+%2B+1
1+=+0+%2B+1
1+=+1
OK



Average/293200: A week ago, Sandy’s seasonal Little League batting average was 360. After five more at bats this week, Sandy’s batting average is up to 400. What is the smallest number of hits that Sandy could have had this season?
1 solutions

Answer 211659 by josmiceli(9664) About Me  on 2010-04-17 10:41:33 (Show Source):
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The batting average is (hits)/(number of times at bat) x 1000
Let x = times at bat last week
Let h = number of hits last week
Let n = number of hits this week
(1) 360%2F1000+=+h%2Fx
and after this week:
(2) 400%2F1000+=+%28h+%2B+n%29%2F%28x+%2B+5%29
------------------------------
This is 2 equations and 3 unknowns, so it isn't
directly solvable, but it can be analyzed
From (1):
(1) 360%2F1000+=+h%2Fx
.36+=+h%2Fx
x+=+h%2F.36
x+=+2.778h
and from (2)
.4+=+%28h+%2B+n%29%2F2.778h+%2B+5%29
.4%2A%282.778h+%2B+5%29+=+h+%2B+n
1.111h+%2B+2+=+h+%2B+n
.111h+%2B+2+=+n
I know that n+%3C=+5
Suppose n+=+1
h ends up being (-), so that doesn't work
Suppose n+=+2. Then h+=+0, and that can't be
Suppose n+=+3
.111h+=+1
h+=+9
From (1)
.36+=+h%2Fx
x+=+9%2F.36
x+=+25
and from (2):
(2) 400%2F1000+=+%28h+%2B+n%29%2F%28x+%2B+5%29
(2) .4+=+%289+%2B+3%29%2F%2825+%2B+5%29
The smallest number of hits Sandy could have got this
season is h+%2B+n, or 12 hits
.4+=+12%2F30
12+=+12
OK








Travel_Word_Problems/293156: a car driving in fog passed a man walking at 3km\hr in a same direction. he could see the car for 4 minute and up to a distance 100 meter
.what was speed of the car?
1 solutions

Answer 211652 by josmiceli(9664) About Me  on 2010-04-17 10:10:52 (Show Source):
You can put this solution on YOUR website!
I think that their relative speed is s+-+3 km/hr
where s is the speed of the car.
The car looks like it's going .1%2F4 km/min
or .1%2F4 km/min x 60 min/hr = 3%2F2 km/hr
s+-+3+=+3%2F2
s+=+9%2F2
The speed of the car is 4.5 km/hr
Hope I got it right


Travel_Word_Problems/292740: An airplne flew for 4 hours with a 20 km/hour tail wind. The return flight against the same wind took 5 hours. Find the speed of the plane in still air.
I am having trouble finding the distance flown to figure out the answer.
1 solutions

Answer 211390 by josmiceli(9664) About Me  on 2010-04-15 20:30:36 (Show Source):
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Let w = wind speed
Let p = speed of plane in still air
p+%2B+w = speed of plane flying with the wind
p+-+w = speed of plane flying against the wind
--------------------
Flying with the wind:
d+=+%28p+%2B+w%29%2A4 km
(1) d+=+%28p+%2B+20%29%2A4 km
Flying against the wind:
d+=+%28p+-+w%29%2A5 km
(2) d+=+%28p+-+20%29%2A5 km
Since d is the same in (1) and (2), they
are equal to eachother
%28p+%2B+20%29%2A4+=+%28p+-+20%29%2A5
4p+%2B+80+=+5p+-+100
p+=+180
The plane's speed in still air is 180 km/hr




Pythagorean-theorem/292741: The base path of a baseball diamond forms a square. If it is 90 ft. from home to first, how far does the catcher have to throw to catch someone stealing second base?
Give your answer as a radical expresion in simplest form and then stimate the lenght to the nearest tenth of a foot.
1 solutions

Answer 211378 by josmiceli(9664) About Me  on 2010-04-15 20:10:26 (Show Source):
You can put this solution on YOUR website!
It is telling you that 90 ft is one
side of the square, and it is asking you
for the distance between opposite corners.
The sides are all equal to 90 ft
and, for a square, the diagonal and a side
are in the ratio sqrt%282%29 to 1,
so I can say sqrt%282%29%2F1+=+x%2F90
Multiply both sides by 90
90%2Asqrt%282%29+=+x
x+=+1.414%2A90
x+=+127.3 ft (rounded to nearest 1/10 th)