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Linear-equations/276677: Please show me how to work with the following word problem:
A train travels 20ft in .5sec. At the same speed, how many feets it travels in 3 seconds?
Thank you.
1 solutions

Answer 201603 by richwmiller(9135) About Me  on 2010-03-03 14:25:23 (Show Source):
You can put this solution on YOUR website!
20/.5=x/3
40/1=x/3
120/3=x/3
x=120
or 20/.5=x/3
60=.5x
120=x


Percentage-and-ratio-word-problems/276658: 3,400 decreased by 18.2%
1 solutions

Answer 201598 by richwmiller(9135) About Me  on 2010-03-03 14:08:15 (Show Source):
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100-18.2=81.8
.818*3400=x


Linear-systems/276659: System of Linear Equations and Problem Solving:
Can someone show me how to set with this word problem please?
An airplane traveled 645 mph with the wind and 575 mph against the wind. Find the speed of the plane in still air and the speed of the wind.
1 solutions

Answer 201596 by richwmiller(9135) About Me  on 2010-03-03 14:00:39 (Show Source):
You can put this solution on YOUR website!

p+w=645
p-w=575
2p=1220
p=610 mph in still air
645-610=35 wind


Geometry_proofs/276603: Explain to an eighth grade student how to purchase a cover for a swimming pool that has a 3-foot walkway all the way around it. The cover must fit over the pool and the walkway.
Demonstrate your procedure by working out an example (problem) using your method.

1 solutions

Answer 201554 by richwmiller(9135) About Me  on 2010-03-03 12:16:34 (Show Source):
You can put this solution on YOUR website!
I would tell the eighth grade student to mind her own business and to have the owners buy the cover.
1- the eighth grade student can't drive.
2-the student doesn't have the money to buy the cover.
3-the pool doesn't belong to the student so the student shouldn't be messing with it.
4- The student shouldn't be trying to install the pool cover mid winter. That should have been done in the fall.
5-I would also inquire as to why the student is so interested in this pool. It sounds very suspicious. Who is putting her up to this? A teacher? I would have an inquiry into the improper conduct of the teacher.


Miscellaneous_Word_Problems/276599: How do we explain logically the results when we use either the substitution or elimination method to solve an inconsistent system? Give an example.

1 solutions

Answer 201549 by richwmiller(9135) About Me  on 2010-03-03 12:08:30 (Show Source):
You can put this solution on YOUR website!
inconsistent systems have no solutions.
so when you try to force a solution when none exists you will get nonsense.


Quadratic_Equations/276593: I find this quite difficult, though I am gaining some level of understanding. I am unsure how to solve for the following 2 quadratic equations Please help
Thanks

1. x2 – 2x – 13 = 0
2. 2x2 – 3x – 5 =0
These are the steps I need to take, just unsure how
a. move the constant term to the right side of the equation
b. multiply each term in the equation by four times the cofficient of the x2 term
c. square the coefficient of the original x term and add it to both sides of the equation
d. take the square root of both sides
e. set the left side of the equation equal to the positive square root of the number on the right side and solve for x
f. set the left side of the equation equal to the negative square root of the number on the right side of the equation and solve for x
1 solutions

Answer 201547 by richwmiller(9135) About Me  on 2010-03-03 12:05:11 (Show Source):
You can put this solution on YOUR website!
Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 1x%5E2%2B-2x%2B-13+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%28-2%29%5E2-4%2A1%2A-13=56.

Discriminant d=56 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--2%2B-sqrt%28+56+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%28-2%29%2Bsqrt%28+56+%29%29%2F2%5C1+=+4.74165738677394
x%5B2%5D+=+%28-%28-2%29-sqrt%28+56+%29%29%2F2%5C1+=+-2.74165738677394

Quadratic expression 1x%5E2%2B-2x%2B-13 can be factored:
1x%5E2%2B-2x%2B-13+=+1%28x-4.74165738677394%29%2A%28x--2.74165738677394%29
Again, the answer is: 4.74165738677394, -2.74165738677394. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+1%2Ax%5E2%2B-2%2Ax%2B-13+%29

Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation ax%5E2%2Bbx%2Bc=0 (in our case 2x%5E2%2B-3x%2B-5+=+0) has the following solutons:

x%5B12%5D+=+%28b%2B-sqrt%28+b%5E2-4ac+%29%29%2F2%5Ca

For these solutions to exist, the discriminant b%5E2-4ac should not be a negative number.

First, we need to compute the discriminant b%5E2-4ac: b%5E2-4ac=%28-3%29%5E2-4%2A2%2A-5=49.

Discriminant d=49 is greater than zero. That means that there are two solutions: +x%5B12%5D+=+%28--3%2B-sqrt%28+49+%29%29%2F2%5Ca.

x%5B1%5D+=+%28-%28-3%29%2Bsqrt%28+49+%29%29%2F2%5C2+=+2.5
x%5B2%5D+=+%28-%28-3%29-sqrt%28+49+%29%29%2F2%5C2+=+-1

Quadratic expression 2x%5E2%2B-3x%2B-5 can be factored:
2x%5E2%2B-3x%2B-5+=+2%28x-2.5%29%2A%28x--1%29
Again, the answer is: 2.5, -1. Here's your graph:
graph%28+500%2C+500%2C+-10%2C+10%2C+-20%2C+20%2C+2%2Ax%5E2%2B-3%2Ax%2B-5+%29

also
(x+1)* (2x-5) = 0


Travel_Word_Problems/276584: If a plane flying from O'Hare travels west at 550 miles per hour and another leaving at the same time travels east at 450 miles per hour, how many hours until the planes are 2600 miles apart?
1 solutions

Answer 201545 by richwmiller(9135) About Me  on 2010-03-03 11:58:26 (Show Source):
You can put this solution on YOUR website!
rt=d
rt+rt=d
550t+450t=2600
1000t=2600
t=2.6 hrs
check
550*2.6+450*2.6=2600
ok


Rectangles/276589: Find the maximum area of a rectangle with a perimeter of 216
1 solutions

Answer 201543 by richwmiller(9135) About Me  on 2010-03-03 11:54:44 (Show Source):
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the max area would be a square.
216/4=54 per side
A=54^2


Percentage-and-ratio-word-problems/276572: Jay Leno’s collection of cars and
motorcycles totals 187. When he checks the air in the
tires he has 588 tires to check. How many cars and how
many motorcycles does he own? Assume that the cars
all have four tires and the motorcycles have two.
1 solutions

Answer 201533 by richwmiller(9135) About Me  on 2010-03-03 11:07:28 (Show Source):
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c+m=187
4c+2m=588
m=80 and c =107


Expressions-with-variables/276521: Use Elimination and substitution to solve the following problem
4x-y=8
-8x+2y=-5
Thanks!!
1 solutions

Answer 201525 by richwmiller(9135) About Me  on 2010-03-03 10:25:46 (Show Source):
You can put this solution on YOUR website!
4x-y=8
-8x+2y=-5
multiply the first by 2
8x-2y=16
-8x+2y=-5
add them
0=11
They do not cross. There are no solutions.


Numbers_Word_Problems/276559: find two numbers whose difference is 200, such that the larger number is 5 times the smaller.
1 solutions

Answer 201523 by richwmiller(9135) About Me  on 2010-03-03 10:19:48 (Show Source):
You can put this solution on YOUR website!
x-y=200
x=5y
5y-y=200
4y=200
y=50
x=250
response:
thank-you for the help. although i don't understand how you got the answer to the problem. however, i really do appreciate the help
The problem says 2 numbers differ by 200
let x be one number and y be the other
x-y=200
Do you see how they differ by 200?
The problem also says that one number is 5 times the other number
so let x=5y
Do you see how x is 5 times y?
so substitute 5y for x in x-y=200
and we get
5y-y=200
4y=200
y=50
but we also know that
x=5y
x=5*50
x=250


Miscellaneous_Word_Problems/276561: Anthony's company made 17 customer calls last week and 22 calls this week. How many calls must be made next week in order to maintain an average of at least 20 for the three-week period?
1 solutions

Answer 201521 by richwmiller(9135) About Me  on 2010-03-03 10:15:59 (Show Source):
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(17+22+x)/3=20
17+22+x=60
39+x=60
x=21
x must be at least 21 calls


Age_Word_Problems/276556: James' age in 11 years will be three times what it was 9 years ago. How old is James now?
1 solutions

Answer 201518 by richwmiller(9135) About Me  on 2010-03-03 10:12:42 (Show Source):
You can put this solution on YOUR website!
j+11=3*(j-9)
j+11=3j-27
38=2j
19=j
check
30=3*10
ok


Trigonometry-basics/276511: please can you help
1) Opposite corners of a small rectangular park are joined by diagonal paths, each 360 m long. what are the dimensions of the park if the paths intersect at a 65 degree angle?
1 solutions

Answer 201516 by richwmiller(9135) About Me  on 2010-03-03 10:10:18 (Show Source):
You can put this solution on YOUR website!
some website rules to remember
one question per submission
and limit of 4 submissions daily
and no similar problems
thank you


Linear_Equations_And_Systems_Word_Problems/276544: Five years ago, Kim's age was half of the age she will be in 8 years. How old is she now?
1 solutions

Answer 201514 by richwmiller(9135) About Me  on 2010-03-03 10:06:06 (Show Source):
You can put this solution on YOUR website!
k-5=1/2*(k+8)
k=18
check
13=1/2*26
13=13
ok


Inequalities/276549: Can you please tell me the answer to this Linear Inequality?
To receive an A grade, a student must average 100 or less but more than 93. If the person received an A in the course and had five grades of 94,90,96,79, and 100 before taking the final exam, what were the possible grades for the final if there were 100 points possible? (assume all six grades are weighted equally)
Let x represent the unknown score.
1 solutions

Answer 201513 by richwmiller(9135) About Me  on 2010-03-03 10:02:57 (Show Source):
You can put this solution on YOUR website!
94+90+96+79+100=459
average is 91.8
(459+x)/6>93
459+x>558
x>99
x=100 is the only possibly grade.


Travel_Word_Problems/276537: person drove for 3 hours on I-10 (interstate 10), then decreased his speed by 10 miles per hour for the next 3 hours. if his total trip was 360 miles, what was his speed the first hour of his trip in miles per hour?
1 solutions

Answer 201509 by richwmiller(9135) About Me  on 2010-03-03 09:55:19 (Show Source):
You can put this solution on YOUR website!
3x+3(x-10)=360
3x+3x-30=360
6x=390
2x=130
x=65 mph first hour
195+165=360


Finance/276548: A person has 17 coins, all nickels and dimes, worth $1.25. How many nickels are there?
1 solutions

Answer 201507 by richwmiller(9135) About Me  on 2010-03-03 09:49:01 (Show Source):
You can put this solution on YOUR website!
n+d=17
5n+10d=125
d=8 n=9
80+45=125


Linear_Equations_And_Systems_Word_Problems/276547: In a student election, 584 students voted for one or the other of two candidates for president. If the winner received 122 more votes than the loser, how many votes were cast for each candidate?
1 solutions

Answer 201506 by richwmiller(9135) About Me  on 2010-03-03 09:47:17 (Show Source):
You can put this solution on YOUR website!
x+x+122=584
x=231
x+122=353


Inequalities/276205: how would you do this problem? -5 < c + 3
1 solutions

Answer 201321 by richwmiller(9135) About Me  on 2010-03-02 16:10:29 (Show Source):
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subtract 3 from both sides
-8

Probability-and-statistics/276135: June, marie, and Billy each have a collection of marbles. June has 20 more marbles than Billy, and Maria has 3 times as many marbles as Billy. If altogether they have 100 marbles, how many marbles does Billy have?
1 solutions

Answer 201320 by richwmiller(9135) About Me  on 2010-03-02 16:03:40 (Show Source):
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j+b+m=100
j=b+20
m=3b
b=16
j=36
m=48


Problems-with-consecutive-odd-even-integers/276188: Three consecutive even integers are such that the square of the first plus the square of the third is 136. Find the three integers
1 solutions

Answer 201318 by richwmiller(9135) About Me  on 2010-03-02 15:56:55 (Show Source):
You can put this solution on YOUR website!
n^2+(n+4)^2=136
n^2+n^2+8n+16=136
2*(n^2+4n+8)=136
n^2+4n+8=68
n^2+4n-60=0
(n+10)*(n-6)=0
n=6 n=-10
(6,8,10) and (-10,-8,-6)
6^2+10^2=136


Triangles/276189: A 45-45-90 triangle has a leg of 4[SQRT(2)]. What is the hypotenuse?

1 solutions

Answer 201315 by richwmiller(9135) About Me  on 2010-03-02 15:45:56 (Show Source):
You can put this solution on YOUR website!
2a^2=c^2
2*(4*sqrt(2))^2=c^2
64=c^2
8=c =hypotenuse


Matrices-and-determiminant/276196: i need help sloving this equation , but grapgine utility to evualate the expression. and round to nearest 3rd decimal if necessary,
55([14 -11] [-22 20])
[-22 19] + [16 6])
1 solutions

Answer 201314 by richwmiller(9135) About Me  on 2010-03-02 15:41:53 (Show Source):
You can put this solution on YOUR website!
there is no equation


Inequalities/276191:
4. Solve the inequality for x: -3x<6           
1 solutions

Answer 201313 by richwmiller(9135) About Me  on 2010-03-02 15:40:27 (Show Source):


Travel_Word_Problems/276198: molder leaves washington at 8:30 AM and average 65 mph hour and his partner Scholy leaves at 9 AM following the same path as molder At 68 Mph what time will scholy will catch up with molder?
1 solutions

Answer 201312 by richwmiller(9135) About Me  on 2010-03-02 15:36:06 (Show Source):
You can put this solution on YOUR website!
rt=d
rt=rt
65*(t+1/2)=68*t
t=65/6
t=10 5/6 hrs=10:48 10 hrs 48 min
they meet at 9+10:48=19:48=7:48 pm
check
65*(65/6+3/6)=68*65/6
65*68/6=68*65/6


Travel_Word_Problems/276065: At 2:00 p.m. two cars start toward each other from towns 240 miles apart. If the rate of one car is 10 mph faster than the other, how fast does each car go if they meet at 5:00 p.m.?
1 solutions

Answer 201270 by richwmiller(9135) About Me  on 2010-03-02 10:54:21 (Show Source):
You can put this solution on YOUR website!
(x+10)*3+3*x=240
x=35
x+10=45
check
3*35+3*45=240
105+135=240
ok


Numeric_Fractions/276062: My 11 yr. old missed school last week. An example of her worksheet:6/2=15/x . I know x is 5 but i don't know a simple way to put it to her so she can figure it out/get it herself. Thanks for any help. P
1 solutions

Answer 201268 by richwmiller(9135) About Me  on 2010-03-02 10:51:06 (Show Source):
You can put this solution on YOUR website!
6/2=15/x
there are several ways to figure this
3=15/x
3x=15
x=5
or
6/2=15/x
multiply both sides by x and both sides by 2
6x=15*2
6x=30
x=5


Divisibility_and_Prime_Numbers/276058: A man is 67 1/12 inches tall and his daughter is 60 8/9 inches tall. How much taller is the man? The man is __ inches taller. Simply your answer. Type an integer or a mixed number.
1 solutions

Answer 201266 by richwmiller(9135) About Me  on 2010-03-02 10:47:05 (Show Source):
You can put this solution on YOUR website!
67 1/12=67 9/108=66 117/108
60 8/9=60 96/108=60 96/108
6 21/108 difference
21/108=7/36
6 7/36 inches taller
I would like to know what crazy ruler was used that gives ninths of an inch!




Numbers_Word_Problems/276051: Jane and Bill went on a picnic. Jane at 1/2 the cupcakes and Bill ate 1/2 the cupcakes plus 3 more. How many cupcakes did they take?
1 solutions

Answer 201265 by richwmiller(9135) About Me  on 2010-03-02 10:39:43 (Show Source):
You can put this solution on YOUR website!
something is wrong with the wording.
if jane ate 1/2 the cupcakes then there are only 1/2 left for bill not 1/2 +3!
if bill ate first then there are not half left for jane!


Number-Line/272457: I have solved this inequality and I want to know how to graph it on a number line:
My answer is:
-2 is greater than b OR b is equal to and greater than -3. Does my line go on forever on each side of does it stop at -3 and -2?
Thank you.
1 solutions

Answer 201261 by richwmiller(9135) About Me  on 2010-03-02 10:28:15 (Show Source):
You can put this solution on YOUR website!
The number line goes on forever but we obviously only use a part of it.
-2>b or b>=-3
I assume you mean equal to or greater than -3 since a number can't be both equal to and greater than -3
so your b is b>-3
if your inequality had said -2>b and b>-3 then we would be limiting b to between -2 and -3 but it doesn't