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josmiceli answered: 9646 problems
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Percentage-and-ratio-word-problems/373440: carlos worked 31.5 hours at a hospital as a volunteer. this represents 87.5% of his schools requirement for community service. how many hours does his school require for community service
1 solutions

Answer 265789 by josmiceli(9649) About Me  on 2010-11-18 20:45:32 (Show Source):
You can put this solution on YOUR website!
Let x = his school's requirement for community service
31.5+=+.875x
x+=+31.5%2F.875
x+=+36
36 hours is the requirement


Mixture_Word_Problems/373434: $9500 is invested, part of it at 10% and part of it at 8%. For a certain year, the total yield is $878.00. How much was invested at each rate?
How much was invested at 10%?
How much was invested at 8%?
1 solutions

Answer 265786 by josmiceli(9649) About Me  on 2010-11-18 20:41:08 (Show Source):
You can put this solution on YOUR website!
Let a = amount invested at 10%
Let b = amount invested at 8%
given:
(1) a+%2B+b+=+9500
.1a+%2B+.08b+=+878
(2) 10a+%2B+8b+=+87800
Multiply both sides of (1) by 8
and subtract (1) from (2)
(2) 10a+%2B+8b+=+87800
(1) -8a+-+8b+=+-76000
2a+=+11800
a+=+5900
and, since
(1) 5900+%2B+b+=+9500
b+=+3600
$5,900 was invested at 10% and $3,600 was invested at 8%
check answer:
.1a+%2B+.08b+=+878
.1%2A5900+%2B+.08%2A3600+=+878
590+%2B+288+=+878
878+=+878
OK


Word_Problems_With_Coins/373028: if i have 20 coins only dimes and quarters and have $3.80 how many quters do i have
1 solutions

Answer 265613 by josmiceli(9649) About Me  on 2010-11-18 02:24:14 (Show Source):
You can put this solution on YOUR website!
Let d = number of dimes
Let q = number of quarters
given:
(1) d+%2B+q+=+20
(2) 10d+%2B+25q+=+380 (in cents)
-------------------------------
Multiply both sides of (1) by 10
and subtract (1) from (2)
(2) 10d+%2B+25q+=+380
(1) -10d+-+10q+=+-200
15q+=+180
q+=+12
And, from (1),
d+%2B+12+=+20
d+=+8
I have 8 dimes and 12 quarters
check answer:
(2) 10d+%2B+25q+=+380
(2) 10%2A8+%2B+25%2A12+=+380
80+%2B+300+=+380
OK


Equations/373047: one canned juice drink is 20% orange juice; another is 5% orange juice. how many liters of each should be mixed together in order to get 15L that is 13% orange juice?
1 solutions

Answer 265611 by josmiceli(9649) About Me  on 2010-11-18 02:16:57 (Show Source):
You can put this solution on YOUR website!
Let a = liters of 20% oj needed
Let b = liters of 5% oj needed
given:
(1) a+%2B+b+=+15
(2) %28.2a+%2B+.05b%29%2F15+=+.13
-------------------------------------
From (2):
(2) .2a+%2B+.05b+=+1.95
(2) 20a+%2B+5b+=+195
Multiply both sides of (1) by 5
and subtract (1) from (2)
(2) 20a+%2B+5b+=+195
(1) -5a+-+5b+=+-75
15a+=+120
a+=+8
And, from (1),
8+%2B+b+=+15
b+=+7
8 liters of 20% oj and 7 liters of 5% oj are needed
check the answer:
(2) %28.2a+%2B+.05b%29%2F15+=+.13
%28.2%2A8+%2B+.05%2A7%29%2F15+=+.13
%281.6+%2B+.35%29%2F15+=+.13
1.95%2F15+=+.13
1.95+=+1.95
OK




Quadratic_Equations/372841: I have pulled my hair out trying to learn this stuff!! If anyone could help me I'd so appreciate it!! thank you!!
Solve using the elimination method. Show your work. If the system has no solution or an infinite number of solutions, state this.
3x + 11y = 34.5
9x – 7y = -16.5
1 solutions

Answer 265538 by josmiceli(9649) About Me  on 2010-11-17 19:38:17 (Show Source):
You can put this solution on YOUR website!
It helps to get all the terminology straight,
otherwise, you can't talk about it
You have:
1st equation:
(term 1) + (term 2) = (term 3)
2nd equation:
(term 1) + (term 2) = (term 3)
What you are trying to do is
get either the (term 1)'s equal to each other
or the (term 2)'s equal to each other.
Then the next step is to multiply both sides
of equation 2 by -1
Then when add the equations, you get:
1st equation:
(term 1) + (term 2) = (term 3)
2nd equation:
-(term 1) - (term 2) = -(term 3)
So, you've gotten rid of either the (term 1)'s or the (term 2)'s
--------------
How do you get (term 1)'s equal to each other?
3x+%2B+11y+=+34.5
9x+-+7y+=+-16.5
Multiply both sides of equation 1 by 3
9x+%2B+33y+=+103.5
Now you can multiply both sides of equation 2 by -1
and add the equations
9x+%2B+33y+=+103.5
-9x+%2B+7y+=+16.5 (note that all the signs are changed)
Adding:
40y+=+120
Divide both sides by 40
y+=+3
Now you can plug this result back into
either equation and find x
Does this help?


Percentage-and-ratio-word-problems/372817: the animal shelter has only dogs and cat's. there are 25% more dogs than cats. what percentage of the animals at the animal shelter are cats? explain your solution
1 solutions

Answer 265533 by josmiceli(9649) About Me  on 2010-11-17 19:16:22 (Show Source):
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Let d = number of dogs
Let c = number of cats
given:
d+=+c+%2B+.25c
The percentage of animals that are cats =
%28c%2F%28c+%2B+d%29%29%2A100
By substitution:
%28c%2F%28c+%2B+c+%2B+.25c%29%29%2A100
%28c%2F2.25c%29%2A100
%281%2F2.25%29%2A100
44.44
The cats are 44.44% of the animals
check:
If there were 125 dogs,
d+=+c+%2B+.25c
125+=+1.25c
c+=+100
%28c%2F%28c+%2B+d%29%29%2A100
%28100%2F%28100+%2B+125%29%29%2A100
%28100%2F225%29%2A100+=+10000%2F225
10000%2F225+=+44.44


Equations/372821: 4 1/6 = r + 6 1/4 i got 1 12/13 is that right?
1 solutions

Answer 265529 by josmiceli(9649) About Me  on 2010-11-17 19:02:47 (Show Source):
You can put this solution on YOUR website!
Get fractions in terms of 1/12's
4 2/12 = r + 6 3/12
+4+=+48%2F12
6+=+72%2F12
48%2F12+%2B+2%2F12++=+r+%2B+72%2F12+%2B+3%2F12
50%2F12+=+r+%2B+75%2F12
r+=+50%2F12+-+75%2F12
r+=+-+25%2F12
check answer:
-25%2F12 = -2 1/12
4 2/12 = r + 6 3/12
4 2/12 = -2 1/12 + 6 3/12
4 + 2 - 6 = 3/12 - 1/12 - 2/12
0 = 3/12 - 3/12
0 = 0
OK


Finance/372802: A car rental company charges a daily rental fee plus a per mile fee over 150 miles. Two different people rent the same style of car for the same number of days. The total bill for one persons rental is $207.50 for a 5-day rental and 180 miles. The total bill for the other persons rental is $212.50 for a 5-day rental and 200 miles.
I need to write a linear system that I can use to find the daily rental fee and the per mile fee over 150 miles.
1 solutions

Answer 265527 by josmiceli(9649) About Me  on 2010-11-17 18:53:57 (Show Source):
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Let d = daily rental fee
Let f = the per mile fee over 150 miles
given:
Person 1: cost of daily rental = 5d
Person 2: cost of daily rental = 5d
Person 1: per mile fee over 150 miles = %28180+-+150%29%2Af+=+30f
Person 2: per mile fee over 150 miles = %28200+-+150%29%2Af+=+50f
------------------
5d+%2B+30f+=+207.5
5d+%2B+50f+=+212.5
Multiply both sides of each equation by 2
10d+%2B+60f+=+415
10d+%2B+100f+=+425
Divide both sides of each equation by 5
2d+%2B+12f+=+83
2d+%2B+20f+=+85


Systems-of-equations/372765: A dehydrated patient needs a 2.6% saline IV. Unfortunately, the hospital only has bags of 8% and 2% saline solutions. How many liters of each solutions should be mixed together to yield 2 liters of the desired concentration.
1 solutions

Answer 265514 by josmiceli(9649) About Me  on 2010-11-17 18:20:20 (Show Source):
You can put this solution on YOUR website!
Let a = liters of 8% solution needed
Let b = liters of 2% solution needed
In words:
(liters of saline)/(liters of solution) = 2.6%
(1) %28.08a+%2B+.02b%29%2F2+=+.026
(2) a+%2B+b+=+2
------------------
From (1):
(1) .08a+%2B+.02b+=+.052
(1) 80a+%2B+20b+=+52
Multiply both sides of (2) by 20 and
subtract from (1)
(1) 80a+%2B+20b+=+52
(2) -20a+-+20b+=+-40
60a+=+12
a+=+.2
And, since
a+%2B+b+=+2
b+=+1.8
.2 liters of 8% solution and 1.8 liters of 2% solution are needed
check answer:
(1) %28.08a+%2B+.02b%29%2F2+=+.026
(1) %28.08%2A.2+%2B+.02%2A1.8%29%2F2+=+.026
(1) %28.016+%2B+.036%29%2F2+=+.026
.052%2F2+=+.026
.052+=+.052
OK


Complex_Numbers/372780: What is the complex conjugate of the (square root of -400) + 17?
1 solutions

Answer 265511 by josmiceli(9649) About Me  on 2010-11-17 18:02:02 (Show Source):
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The complex conjugate of sqrt%28-400%29+%2B+17 = -sqrt%28-400%29+%2B+17
-sqrt%28-400%29+%2B+17+=+-20i+%2B+17


test/368101: A fish was caught whose tail weighed 9 lb. Its head weighed as much as it's tail pluse half its body. Its body weighed as much as it's head and tail. What did the fish weigh?
1 solutions

Answer 262328 by josmiceli(9649) About Me  on 2010-11-08 19:51:38 (Show Source):
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Let t = weight of tail
Let b = weight of body
Let h = weight of head
given:
t+=+9
h+=+t+%2B+b%2F2
b+=+h+%2B+t
---------------
By substitution:
h+=+9+%2B+b%2F2
2h+=+18+%2B+b
(1) 2h+-+b+=+18
and
b+=+h+%2B+9
(2) h+-+b+=+-9
Subtract (2) from (1)
(1) 2h+-+b+=+18
(2) -h+%2B+b+=+9
h+=+27
And, since,
b+=+h+%2B+9
b+=+27+%2B+9
b+=+36
The fish weighed 9+%2B+27+%2B+36+=+72 pounds
check answer:
h+=+t+%2B+b%2F2
27+=+9+%2B+36%2F2
27+=+9+%2B+18
27+=+27
and
b+=+h+%2B+t
36+=+27+%2B+9
36+=+36
OK


Numeric_Fractions/367722: What is 3 2/3 over 7/5 = 3/7 over x?
1 solutions

Answer 262125 by josmiceli(9649) About Me  on 2010-11-08 11:39:19 (Show Source):


Quadratic_Equations/367310: solve
+x%5E%282%2F3%29-2x%5E%281%2F3%29-8=0+
1 solutions

Answer 261819 by josmiceli(9649) About Me  on 2010-11-07 16:23:07 (Show Source):
You can put this solution on YOUR website!
+x%5E%282%2F3%29-2x%5E%281%2F3%29-8=0+
Let 1%2F3+=+z
+x%5E%282z%29-2x%5Ez-8=0+
x%5E%282z%29+-+2x%5Ez+%2B+1+=+8+%2B+1
%28x%5Ez+-+1%29%5E2+=+9
x%5Ez+-+1+=+3
x%5Ez+=+4
Take the zth root of both sides
x+=+4%5E%281%2Fz%29
Since z+=+1%2F3,
x+=+4%5E3
x+=+64


Exponents-negative-and-fractional/367300: How do I solve
81^-3/4
1 solutions

Answer 261814 by josmiceli(9649) About Me  on 2010-11-07 16:12:44 (Show Source):
You can put this solution on YOUR website!
81%5E%28-3%2F4%29
Note that 81+=+3%5E4
Rewrite the problem as:
%283%5E4%29%5E%28-3%2F4%29
I can rewrite this as:
%283%5E%28-3%29%29%5E%284%2F4%29
This equals
3%28-3%29+=+1%2F3%5E3
1%2F3%5E3+=+1%2F27


Travel_Word_Problems/367292: Two joggers are running around an oval track in opposite directions. One jogger runs around the track in 56 seconds. They meet every 24 seconds. How mant seconds does it take the second jogger to run around the track?
1 solutions

Answer 261810 by josmiceli(9649) About Me  on 2010-11-07 16:03:58 (Show Source):
You can put this solution on YOUR website!
Each jogger cuts down the distance between them as they jog.
They are always approaching each other at their combined speeds
Jogger #1 has a speed of (1 trip around)/56 sec
At the sum of their speeds, (1 trip around)/24 sec
Let s = speed of Jogger #2
1%2F56+%2B+s+=+1%2F24
Multiply both sides by 168
3+%2B+168s+=+7
168s+=+4
s+=+1%2F42
The 2nd Jogger takes 42 sec to go around track


Quadratic_Equations/366861: The number of tickets sold each day for an upcoming performance of handel's Messiah is givn by N(x)=-0.4x^2+10.4x+10 where x is the number of days since the concert was first announced. When will daily sales peak and how many tickets will be sold that day? Pleas show work Thank you
1 solutions

Answer 261552 by josmiceli(9649) About Me  on 2010-11-06 17:51:08 (Show Source):
You can put this solution on YOUR website!
+N%28x%29=-.4x%5E2%2B10.4x%2B10
The peak is at x+=+-b%2F%282a%29 when the
equation is in the form ax%5E2+%2B+bx+%2B+c
a+=+-.4
b+=+10.4
+-b%2F%282a%29+=+-10.4%2F-.8
x+=+13
Sales will peak 13 days after concert is announced
+N%28x%29=-.4x%5E2%2B10.4x%2B10
+N%2813%29=-.4%2A13%5E2%2B10.4%2A13+%2B+10
Solve for N%2813%29+


Age_Word_Problems/366640: Erica and Rachel are both 90 years old. Breena, on the other hand, is half again as old as she was when she was half again as old as she was when she lacked five years of being half as old as she is now. How old is Breena?
1 solutions

Answer 261451 by josmiceli(9649) About Me  on 2010-11-06 07:51:08 (Show Source):
You can put this solution on YOUR website!
Let x = her age now
x%2F2 = half as old as she is now
x%2F2+-+5 = lacking 5 years of being half as old as she is now
%283%2F2%29%2A%28x%2F2+-+5%29 = half again as old as she was when she lacked
five years of being half as old as she is now.
+%283%2F2%29%2A%283%2F2%29%2A%28x%2F2+-+5%29 = half again as old as she was when she was
half again as old as she was when she lacked five years
of being half as old as she is now.
She is this age now, so
x+=+%283%2F2%29%2A%283%2F2%29%2A%28x%2F2+-+5%29
x+=+%289%2F4%29%2A%28x%2F2+-+5%29
x+=+%289%2F8%29%2Ax+-+45%2F4
%289%2F8%29%2Ax+-+%288%2F8%29%2Ax+=+90%2F8
x+=+90
Breena is 90 also


Quadratic_Equations/366783: What is the distance between the points where the graph of y = - 2x^2 - x + 15
crosses the x-axis?
1 solutions

Answer 261450 by josmiceli(9649) About Me  on 2010-11-06 07:32:14 (Show Source):
You can put this solution on YOUR website!
-2x%5E2+-+x+%2B+15
Find the roots, which are the x-axis crossings.
Use quadratic formula
x+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
a+=+-2
b+=+-1
c+=+15
x+=+%28-%28-1%29+%2B-+sqrt%28+%28-1%29%5E2-4%2A%28-2%29%2A15+%29%29%2F%282%2A%28-2%29%29+
x+=+%28+1+%2B-+sqrt%28+1+%2B+120+%29%29%2F+-4+
x+=+%281+%2B+11%29%2F-4
x+=+-3
and
x+=+%281+-+11%29%2F-4
x+=+5%2F2
The difference between the roots is 5%2F2+-+%28-3%29+=+11%2F2
Here's the plot:
+graph%28+400%2C+400%2C+-5%2C+5%2C+-5%2C+20%2C+-2x%5E2+-+x+%2B+15%29+


Quadratic_Equations/366752: please help me find the find real solution to 2x%5E4-5x%5E2-12=0
1 solutions

Answer 261417 by josmiceli(9649) About Me  on 2010-11-06 01:29:57 (Show Source):
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2x%5E4+-+5x%5E2+-+12=0
z+=+x%5E2
2z%5E2+-+5z+-+12+=+0
Use quadratic formula
z+=+%28-b+%2B-+sqrt%28+b%5E2-4%2Aa%2Ac+%29%29%2F%282%2Aa%29+
a+=+2
b+=+-5
c+=+-12
z+=+%28-%28-5%29+%2B-+sqrt%28+%28-5%29%5E2+-+4%2A2%2A%28-12%29+%29%29%2F%282%2A2%29+
z+=+%28+5+%2B-+sqrt%28+25+%2B+96+%29%29%2F4+
z+=+%28+5+%2B-+sqrt%28+121+%29%29%2F4+
z+=+%285+%2B+11%29%2F4
z+=+4
and
z+=+%285+-+11%29%2F4
z+=+-3%2F2
And since z+=+x%5E2,
x%5E2+=+4
x+=+2
x+=+-2
These are the real solutions
z+=+-3%2F2 gives 2 imaginary solutions





Radicals/366749: please help me find the real solution of this equation +2%2B+sqrt%28+12-2x%29=+x+
1 solutions

Answer 261414 by josmiceli(9649) About Me  on 2010-11-06 01:19:18 (Show Source):
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+2%2B+sqrt%28+12-2x%29=+x+
Subtract 2 from both sides
sqrt%2812+-+2x%29+=+x+-+2
Square both sides
12+-+2x+=+x%5E2+-+4x+%2B+4
x%5E2+-+2x++=+8
x%5E2+-+2x+%2B+1+=+8+%2B+1
%28x+-+1%29%5E2+=+9
Take the square root of both sides
x+-+1+=+3
x+=+4
and
x+-+1+=+-3
x+=+-2 This only works if the square root is negative)
The real solution is x = 4



Quadratic-relations-and-conic-sections/366722: Write the equation for the parabola which opens left, has its vertex on the origin, and passes through the point (-3/2),1)
1 solutions

Answer 261412 by josmiceli(9649) About Me  on 2010-11-06 01:10:12 (Show Source):
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It would be of the form x+=+-ay%5E2+%2B+by+%2B+c
If the vertex is at the origin, then I can write
0+=+-a%2A0+%2B+b%2A0+%2B+c, so c+=+0
If it includes (-3/2,1),
-3%2F2+=+-a%2A1%5E2+%2B+b%2A1
(1) b+-+a+=+-3%2F2
By symmetry, it must also pass through (-3/2,-1), so
-3%2F2+=+-a%28-1%29%5E2+%2B+b%2A%28-1%29
(2) -b+-+a+=+-3%2F2
Add (1) and (2)
-2a+=+-3
a+=+3%2F2
And, since
(1) b+-+a+=+-3%2F2
b+=+-3%2F2+%2B+a
b+=+-3%2F2+%2B+3%2F2
b+=+0
The equation is
x+=+-%283%2F2%29%2Ay%5E2



Graphs/366748: find the slope is it exists
5x-6y=12
1 solutions

Answer 261410 by josmiceli(9649) About Me  on 2010-11-06 00:56:17 (Show Source):
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Get it into the form y+=+mx+%2B+b
where m is the slope
5x+-+6y+=+12
Add 6y to both sides
5x+=+6y+%2B+12
Subtract 12 from both sides
5x+-+12+=+6y
Divide both sides by 6
y+=+%285%2F6%29%2Ax+-+2
m+=+5%2F6
The slope is 5/6


Miscellaneous_Word_Problems/366609: Find the slope if it exists, of the line containing the points [-1 1/2] and [-10 1/2]
1 solutions

Answer 261276 by josmiceli(9649) About Me  on 2010-11-05 16:18:01 (Show Source):
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The points are in the format (x1,y1) and (x2,y2).
Notice that y1 = 1/2 and y2 = 1/2
If there is no change in y for any 2 points on a line,
then that line has to be vertical, or slope = infinity
the equation of the line is y+=+1%2F2


Polynomials-and-rational-expressions/366571: Choose two trinomials from the list below to factor. Using complete sentences, explain how to factor each one. Be sure that the final factorization (or "answer") is a part of your explanation.
2x2 + 13x + 15
2x2 + 27x + 13
5x2 − 2x − 7
10x2 − 7x − 3
8x2 − 11x + 3

HELP PLEASE??
1 solutions

Answer 261275 by josmiceli(9649) About Me  on 2010-11-05 16:13:44 (Show Source):
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The second one, 2x%5E2+%2B+27x+%2B+13, can be solved by
careful inspection.
First I notice that 2%2A13+%2B+1+=+27. I want to arrange
the factors so I get this result for the coefficient of x
%282x+%2B+1%29%2A%28x+%2B+13%29 accomplishes this.
---------------------------
For the 4th one, 10x%5E2++-+7x++-+3 , I try 10x and x
for the factors of 10x%5E2. Then I try -1 and 3
for the factors of -3. This gives me
%2810x+%2B+3%29%2A%28x+-+1%29 as the answer with -7 as the coefficient of x


Mixture_Word_Problems/366493: Soybean meal is 14% protein; cormeal is 7% protein. How many pounds of each should be mixed together in order to get 280-lb mixture that is 11% protein?
How many pounds of the cornmeal should be in the mixture?
How many pounds of the soybean meal should be in the mixture?
1 solutions

Answer 261168 by josmiceli(9649) About Me  on 2010-11-05 09:57:25 (Show Source):
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Let c = pounds of cornmeal needed
Let s= pounds of soybean meal needed
given:
Pounds of protein in c pounds of cornmeal:
.07c
Pounds of protein in s pounds of soybean meal
.14s
(1) c+%2B+s+=+280
----------------
In words:
(pounds of protein in final mixture)/(total pounds of final mixture) = 11%
%28.07c+%2B+.14s%29%2F280+=+.11
.07c+%2B+.14s+=+30.8
7c+%2B+14s+=+3080
divide both sides by 7
(2) c+%2B+2s+=+440
Subtract (1) from ()
(2) c+%2B+2s+=+440
(1) -c+-+s+=+-280
s+=+160
and, since
c+%2B+s+=+280
c+=+120
120 pounds of cornmeal and 160 pounds of soybean meal are needed
check answer:
%28.07c+%2B+.14s%29%2F280+=+.11
%28.07%2A120+%2B+.14%2A160%29%2F280+=+.11
%288.4+%2B+22.4%29%2F280+=+.11
8.4+%2B+22.4+=+30.8
30.8+=+30.8
OK


Miscellaneous_Word_Problems/366383: A health clinic uses a solution of bleach to sterilize petri dishes in which cultures are grown. The sterilization tank contains 120 gal of a solution of 4% ordinary household bleach mixed with pure distilled water. New research indicates that the concentration of bleach should be 6% for complete sterilization. How much of the solution should be drained and replaced with bleach to increase the bleach content to the recommended level?
1 solutions

Answer 261079 by josmiceli(9649) About Me  on 2010-11-04 22:33:01 (Show Source):
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Let x = gallons of 4% solution to be drained
given:
Bleach in 4% solution:
.04%2A120+=+4.8 gal
Bleach in removed portion:
.04x
Gallons of bleach added:
x
----------
In words:
(initial gallons of bleach - bleach removed + bleach added)/(total gallons) = 6%
%284.8+-+.04x+%2B+x%29%2F120+=+.06
4.8+-+.04x+%2B+x+=+7.2
.96x+=+2.4
x+=+2.5
2.5 gallons of 4% solution must be drained
and replaced with pure bleach


Numbers_Word_Problems/366367: I am a number between 70 and 100. My ones digit is 1 more than my tens digit. I am a prime number. What number am I?
1 solutions

Answer 261068 by josmiceli(9649) About Me  on 2010-11-04 21:56:50 (Show Source):
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I can eliminate 70, 100, 99, and 98, which all have divisors
So I'm left with 71 through 97
I can eliminate all numbers ending in 2,4,5,6, and 8, since they
all have divisors. That leaves number ending in 1,3,7, or 9
The tens digit has to be 7,8, or 9. If the ones digit is 1 more
than the tens digit, then the possible numbers are just one: 89


Word_Problems_With_Coins/366373: Luis and Julia have the same number of coins. Luis has only dimes and Julia has only quaters. If Julia has $1.80 more than Luis does, how many coins do each have ?
1 solutions

Answer 261061 by josmiceli(9649) About Me  on 2010-11-04 21:44:59 (Show Source):
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q+=+d
25q+-+10d+=+180 (in cents)
By substitution:
25q+-+10q+=+180
15q+=+180
q+=+12
d+=+12
Each has 12 coins


Travel_Word_Problems/366347: a car travels down the highway at 60km/hr for2.5hours .How far has the car gone?
1 solutions

Answer 261053 by josmiceli(9649) About Me  on 2010-11-04 21:28:04 (Show Source):
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d+=+r%2At
d+=+60%2A2.5
d+=+150
The car went 150 km


Money_Word_Problems/366356: If you spent $78.00 on clothing and the sales tax was 4.5%, how much change should you get from $100.00?
1 solutions

Answer 261050 by josmiceli(9649) About Me  on 2010-11-04 21:26:20 (Show Source):
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78+%2B+.045%2A78+=+81.51
100+-+81.51+=+18.49
You should get $18.49 change


Linear-equations/366319: Translate to an equation:
f $50 poker chips and t $20 poker chips total $400
Determine three different combinations of $50 poker chips and $20 poker chips that total $400
1 solutions

Answer 261044 by josmiceli(9649) About Me  on 2010-11-04 21:22:47 (Show Source):
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50f+%2B+20t+=+400
5f+%2B+2t+=+40
f+%3C+8 since if f+=+8, there are no $20 chips
Suppose f+=+7
35+%2B+2t+=+40
2t+=+5 -can't have 1/2 a chip
-----------
Suppose f+=+6
30+%2B+2t+=+40
2t+=+10
t+=+5
------------
Suppose f+=+4
20+%2B+2t+=+40
2t+=+20
t+=+10
------------
Suppose f+=+2
10+%2B+2t+=+40
2t+=+30
t+=+15