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Travel_Word_Problems/341863: A car is traveling on a road that is perpendicular to a railroad track. When the car is 30 meters from the crossing, the car's new collison dector warns the driver that there is a train 50 meters from teh car and heading toward the same crossing. How far is the train form the car?
1 solutions

Answer 244766 by mananth(12270) About Me  on 2010-09-12 02:33:14 (Show Source):
You can put this solution on YOUR website!
The car , the crossing & the train are at right angles to each other.
the hypotenuse = 50 m
the leg =30 m
other leg = (sqrt(50^2-30^2)
sqrt(2500-900)
=sqrt 1600
=40 m.
Train is 40 m from the crossing


Linear-systems/341869: how to get the answer of the following?
1.) The perimeter of an isosceles triangle is 36 cm. The total length of the two congruent legs is 12 centimeters more than one half the length of the base. Find the lengths of the three sides.
1 solutions

Answer 244765 by mananth(12270) About Me  on 2010-09-12 02:27:24 (Show Source):
You can put this solution on YOUR website!
let the base = x
let congruent side be y
2y+x=36 .....................1
2y= x/2 +12
multiply by 2
4y=x+24
4y-x=24.......................2
add eq 1 & eq 2
6y=36+24
6y=60
divide by 6
y= 60/6
y=10 conguent side
plug value of y in equation 1
2*10+x=36
20+x=36
x=36-20
x=16 the base
CHECK
16+10+10 = 36
.....


Angles/341870: angle A is nine less than the measure of angle B. if angles A & B form a linear pair, what are their measures?
1 solutions

Answer 244764 by mananth(12270) About Me  on 2010-09-12 02:19:55 (Show Source):
You can put this solution on YOUR website!
let B be x
A = x-9
x-9+x=180
2x=180+9
2x=189
x= 189/2
x=94.5 deg
Angle B = 94.5-9
83.5 deg


Numbers_Word_Problems/341853: If 9 is subracted from a number and this difference is doubled, the result is 12 more than the number, what is the number.
1 solutions

Answer 244756 by mananth(12270) About Me  on 2010-09-11 23:55:05 (Show Source):
You can put this solution on YOUR website!
let x be the number
9 is subtracted = x-9
it is doubled= 2(x-9)
2(x-9)= x+12
2x-18=x+12
2x-x=18+12
x=30


Expressions-with-variables/341842: How would you solve-2c+3(c+15)=c-7(-c+3)-9(-8+5c)?
1 solutions

Answer 244755 by mananth(12270) About Me  on 2010-09-11 23:51:54 (Show Source):
You can put this solution on YOUR website!
-2c+3(c+15)=c-7(-c+3)-9(-8+5c)
-2c+3c+45=c+7c-21+72-45c
bring all the terms on LHS
-2c+3c-c-7c+45c=-45-21+72
38c=6
divide by 38
c= 6/38
c=3/19


Linear-systems/341841: A mother is three times as old as her daughter. Nine years ago, she was six times as old a her daughter. Find the present age of each.
1 solutions

Answer 244746 by mananth(12270) About Me  on 2010-09-11 23:14:33 (Show Source):
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let daughter be x years now
mother is 3x now.
9 years ago
daughter = x-9
mother = 3x-9
..
3x-9 = 6(x-9)
3x-9 = 6x -54
6x-3x= 54 -9
3x=45
divide by 3
x= 15 daughter's age
mother's age = 3x = 3*15 = 45 years


Mixture_Word_Problems/341819: A large tank contains 100 gallons of pure water. How many gallons of a saline solution containing 25% salt must be added to obtain a solution that has 10% salt ?
1 solutions

Answer 244737 by mananth(12270) About Me  on 2010-09-11 22:01:21 (Show Source):
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water 100 gallons 0%
saline 25% x gallons
total 10% x+100
..
0+ 25x=10(x+100)
25x=10x+1000
25x-10x=1000
15x= 1000
x= 1000/15
x= 66.66 gallons of water


Mixture_Word_Problems/341817: Juan mixes 25 mL of a 15% acid solution with 60 mL of a 25% acid solution and 48 mL of a 50% acid solution. About what percent acid is the final solution?
If you could please help me figure this out with using only one variable (perferrably x) that would be great...thanks!!!
1 solutions

Answer 244735 by mananth(12270) About Me  on 2010-09-11 21:05:16 (Show Source):
You can put this solution on YOUR website!
Juan mixes 25 mL of a 15% acid solution with 60 mL of a 25% acid solution and 48 mL of a 50% acid solution. About what percent acid is the final solution?
25ml 15%
60 ml 25%
48 ml 50%
Let percent in thefinal solution be x
and quantity will be 133 ml
25*15+60*25+48*50=133*x
375+1500+2400=133x
4275 =133x
x= 424/133
x= 32.14%


Angles/341806: Angles A, B, C. Angle A is twice as large plus 7 as angle B. Angle C is 61 degrees larger than angle B. What are the measures of all 3 angles?
1 solutions

Answer 244732 by mananth(12270) About Me  on 2010-09-11 20:55:12 (Show Source):
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Angle B = x
Angle A = 2x+7
Angle C =x+61
...
x+2x+7+x+61 = 180
4x+68=100
4x= 112
x= 28 angle B
angle A = 2x+7 = 2*28+7=63
angle C = x+61=28+61=89
..


Travel_Word_Problems/341813: what must be your average speed in order to travel 220 km in 2.25 hours
1 solutions

Answer 244731 by mananth(12270) About Me  on 2010-09-11 20:50:09 (Show Source):
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speed+=+distance+%2F+time
distance = 220 km
time = 2.25 hours 220/2.25
= 97.7 km/h


Mixture_Word_Problems/341603: The radiator in a car is filled with a solution of 70% antifreeze and 30% water. The manufacturer of the antifreeze suggests that for summer driving, optimal cooling of the engine is obtained with only 50% antifreeze. If the capacity of the radiator is 3.5 L, how much coolant should be drained and replaced with water to reduce the antifreeze concentration to the recommended level?
1 solutions

Answer 244614 by mananth(12270) About Me  on 2010-09-11 06:53:38 (Show Source):
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Let water required be x L
70% antifreeze = 3.5 -x L
..
total 50% 3.5 L
..
0+0.7(3.5-x)=0.5*3.5
2.45-0.7x=1.75
-0.7x=1.75-2.45
-0.7x= -0.70
x= 1 L
1 liter 70% has to be drained and 1 L water added.


Mixture_Word_Problems/341604: A two-acre building lot is five times as long as it is wide. What are its dimensions?
1 solutions

Answer 244613 by mananth(12270) About Me  on 2010-09-11 06:43:49 (Show Source):
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1 acre = 43560 sq. ft.
2 acre = 87120 sq.ft.
..
let width be x
length = 5x
Area = L*W
A=5x*x
A= 5x^2
5x^2=87120
x^2=17424
x= 132 feet the width
..
length = 5x
=5*132
=660 feet the length


Polynomials-and-rational-expressions/341606: 1. (x+4)/(x)-(2x-5)/(x+1)
2. (2-x)/(2x+6)+ x/(x^2-9)

Could someone help me work this problem out because I don't understand how to solve these?
1 solutions

Answer 244612 by mananth(12270) About Me  on 2010-09-11 06:31:51 (Show Source):
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%28x%2B4%29%2F%28x%29-%282x-5%29%2F%28x%2B1%29
LCD = x(x+1)
%28%28x-4%29%28x%2B1%29+-+%282x-5%29%2Ax%29%2Fx%28x%2B1%29
%28x%5E2-3x-4-2x%5E2%2B5x%29%2Fx%28x%2B1%29
%28x%5E2%2B2x%2B1%29%2Fx%28x%2B1%29
%28x%2B1%29%5E2%2Fx%28x%2B1%29
%28x%2B1%29%2Fx
2. (2-x)/(2x+6)+ x/(x^2-9)
%282-x%29%2F%282%28x%2B3%29%29%2B+x%2F%28x%2B3%29%28x-3%29
2(x-3) = LCD
%282-x%29%28x-3%29%2B2x%28x-3%29%2F2%28x-3%29
%282x-6-x%5E2%2B3x%2B2x%5E2-6x%29%2F2%28x-3%29
x%5E2-x-6%29%2F2%28x-3%29
%28x-3%29%28x%2B2%29%2F%28x-3%29
%28x%2B2%29


Bodies-in-space/341609: The two right circular cylinders A and B above have diameters of 8 and 12 respectively. If the volume of B is twice the volume of A, what is the ratio of the height of A to the height of B?
a 4/9 b 1/2 c 2/3 d 8/9 e 9/8
1 solutions

Answer 244611 by mananth(12270) About Me  on 2010-09-11 06:12:29 (Show Source):


Geometry_Word_Problems/341610: A cereal box has a volume of 176 cubic inches. When it stands upright, its base has an area of 16 square inches. If a supermarket displays the box standing upright on a display shelf, what is the minimum number of inches between that shelf and the one above it?
(a) 8 (b)11 (c) 16 (d) 160 (e) 256
1 solutions

Answer 244610 by mananth(12270) About Me  on 2010-09-11 06:03:18 (Show Source):


Geometry_Word_Problems/341611: All the dimensions of a certain rectangular solid are integers greater than 1. If the volume is 126 cubic inches and the height is 6 inches, what is the perimeter of the base?
(a) 10 (b)16 (c) 20 (d) 21 (e) 27
1 solutions

Answer 244609 by mananth(12270) About Me  on 2010-09-11 05:50:06 (Show Source):
You can put this solution on YOUR website!
Volume = 126
height =6
area of base = 126/6 = 21 inches
L*W = 21
The dimensions of base = 7*3 =21
7" by 3"
The perimeter = 2*(L+W)
P= 2*(7+3)
P=20 inches


Bodies-in-space/341612: If the area of one face of a cube is 16, what is the volume of the cube?
(a) 4 (b) 12 (c) 48 (d) 64 (e) 256
1 solutions

Answer 244608 by mananth(12270) About Me  on 2010-09-11 05:45:20 (Show Source):
You can put this solution on YOUR website!
area of one face of the cube = 16
so side = 4.
volume of cube = side^3
=4^3
=64


Inverses/341615: I need to know how to work out the reciprocal of decimals and normal numbers for coursework, I don't understand what everyone else is saying. >.<
Can you help me, Please?
1 solutions

Answer 244607 by mananth(12270) About Me  on 2010-09-11 05:42:07 (Show Source):


Travel_Word_Problems/341614: what is the time to travel between two cities? The total distance is 960 miles. At an average of 75mph, how long would it take me? (Ruling out stopping for gas and food.) any help would be greatly appreciated. thank you
1 solutions

Answer 244606 by mananth(12270) About Me  on 2010-09-11 05:41:01 (Show Source):
You can put this solution on YOUR website!
+Time+=+distance+%2F+speed
distance = 960 miles
speed = 75 mph
..
+time+=+960%2F75
= 12.8 hours
or 12 hours 48 minutes


Travel_Word_Problems/341582: Two trains leave the station at the same time, one heading west and the other east. The westbound train travels 20 miles per hour slower than the eastbound train. If the two trains are 900 miles apart after 5 hours, what is the rate of the westbound train?
1 solutions

Answer 244605 by mananth(12270) About Me  on 2010-09-11 00:31:11 (Show Source):
You can put this solution on YOUR website!
Two trains leave the station at the same time, one heading west and the other east. The westbound train travels 20 miles per hour slower than the eastbound train. If the two trains are 900 miles apart after 5 hours, what is the rate of the westbound train?
..
let east bound train (A) speed =x mph
west bound train(B) speed will be x-20 mph.
..
Distance = speed * time
distance traveled by train A = 5x
distance traveled by train B = 5*(x-20)
..
5x+5(x-20)=900
5x+5x-100 =900
10x=900+100
10x=1000
x=100 mph east bound train
west bound train = 100-20=80 mph
..


Linear-equations/341587: graph the line with slope -1/3 passing though the point(3,5)
1 solutions

Answer 244604 by mananth(12270) About Me  on 2010-09-11 00:20:41 (Show Source):
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plug the value of m=-1/3 & (3,5)
..
5=-1/3*(3)+b
5=-1+b
b=6
..
y= (-1/3) x +6
graph%28500%2C500%2C-2%2C30%2C-8%2C8%2C%28%28-x%2F3%29%2B6%29%29


test/341596: John spent $352 on fencing for his dog pen. The fencing cost $11.00 per foot. He built a rectangular pen 10 feet in length. If he had planned better, he could have increased the area avalible to his dog by a maximum of how many square feet?
1 solutions

Answer 244603 by mananth(12270) About Me  on 2010-09-10 23:55:58 (Show Source):
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$352 for the fence @ $11 . foot.
so total fencing = 352/11= 32 feet.
..
Perimeter P = 2(L+W)
32= 2(L+W)
32/2 = L+W
16= 10+W
W= 16-10
W= 6 feet.
..
The area of the pen = 10*6 = 60 sq. ft.
we know square gives maximum area.
so 8*8 =64
He could have gained 4 sq.ft


Money_Word_Problems/341368: There were 284 tickets sold for a basketball game. The activity cardholder's ticket cost $1.25 and the non cardholders' tickets cost $2.25. The total amount of money collected was $521. How many of each kind of ticket were sold?
How many activity cardholders ticket were sold?
How many non-cardholders ticket were sold?
1 solutions

Answer 244440 by mananth(12270) About Me  on 2010-09-10 10:24:07 (Show Source):
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let x be the number of activity cardholder's tickets sold at $1.25
non - 284-x tickets $2.25
Total revene = $521
..
1,25x+(284-x)*2.25 = 521
1.25x + 639-2.25x=521
-x= -639-521
x= 118 activity cardholder's tickets
284-118= 166 non activity cardholder's tickets


Graphs/341355: Write the equation of the line that passes through (2, 2) and (6, 3) in standard form
Thank you
1 solutions

Answer 244422 by mananth(12270) About Me  on 2010-09-10 09:23:11 (Show Source):
You can put this solution on YOUR website!
The slope of line passing through these points
y2-y1 / x2-x1
=(3-2) / (6-2)
=1/4 .
y= mx+b is the equation of the line.
plug any value from the two points.
2=1/4 * x+b
2=1/2 +b
2-1/2 = b
3/2 = b
..
so the equation of the line = y=1/4 (x) + 3/2


Travel_Word_Problems/341350: Joe drove 210 km at 70 km/h and then another 210 km at 105 hm/h. It took Bill the same length of time to drive the entire 420 km at constant speed. What was Bill's speed?
1 solutions

Answer 244421 by mananth(12270) About Me  on 2010-09-10 09:10:43 (Show Source):
You can put this solution on YOUR website!
Joe drove 210 km at 70 km/h and then another 210 km at 105 hm/h. It took Bill the same length of time to drive the entire 420 km at constant speed. What was Bill's speed?
..
+time+=+distance+%2F+speed
Time taken by Joe = +%28210%2F70%29+%2B+%28210%2F105%29
Time taken = 3 + 2 = 5 hours.
..
Bill takes same time to go 420 kms .
Bill's speed = 420/5 = 84 km/h


Divisibility_and_Prime_Numbers/341354: is 1403 divisible by 3?
1 solutions

Answer 244420 by mananth(12270) About Me  on 2010-09-10 09:02:48 (Show Source):
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1+4+0+3 =8
8 is not divisible by 3
so the number 1403 is not divisible by 3


Radicals/341334: Hello!
I have this problem and not quite sure if I did it right.
Write the expression in lowest terms. Assume that all variables represent positive real numbers:
54+36√21
--------
45
Will this equal:
6+4√21
------
5

or can √21 be factored more with √3 and √7?
Thank you!
1 solutions

Answer 244409 by mananth(12270) About Me  on 2010-09-10 08:18:33 (Show Source):


Miscellaneous_Word_Problems/341161: The manager at Cream of the Crop bought a load of watermelons for $180. She priced the melons so that she would make $1.50 profit on each melon. When all but 20 had been sold, the manager had recovered her initial investment. How many did she buy originally?

I am totally confuse with this word problem. I can't for the life of me figure it out, so can somone please help me.

1 solutions

Answer 244404 by mananth(12270) About Me  on 2010-09-10 05:48:05 (Show Source):
You can put this solution on YOUR website!
let her buy x melons.
so cost of 1 melon = 180/x
..
she sold each at (180/x) + 1.5
when she had sold x-20 melons she got back $180
..
selling price of 1 melon * number of melons sold = 180
((180/x)+1.5)*(x-20)= 180
(180/x +3/2 )* (x-20)=180
(360+3x)/2x*(x-20)= 180
(360+3x)(x-20)= 180*2x
-7200-60x+360x+3x^2= 360x
re-arrange the terms
3x^2-60x-7200= 0
divide by 3
x^2-20x-2400=0
x^2-60x+40x-2400=0
x(x-60)+40(x-60)=0
(x-60)(x+40)=-0
So x = 60 the number of lemons she bought.


Numeric_Fractions/341152: Chris bought 1 and 3/4 pounds of nuts. Two-thirds of this amount was used at a dinner party. How many pounds of nuts were used?
1 solutions

Answer 244403 by mananth(12270) About Me  on 2010-09-10 05:22:13 (Show Source):
You can put this solution on YOUR website!
1 (3/4) pounds
2/3 was used
..
1 3/4 = 7/4
..
2/3 * 7/4 = 7/6 was used.
1 1/6 pound was used.


Trigonometry-basics/341306: please help me out with this

A communication company erects a 81-foot tall cellular telephone tower on level ground. Determine the angle of depression, theta(in degree), from the top of the tower to a point 59 feet from the base of the tower. Round answer to the decimal places.
1 solutions

Answer 244402 by mananth(12270) About Me  on 2010-09-10 04:22:25 (Show Source):
You can put this solution on YOUR website!
+Tan%28theta%29=perpendicular+%2Fbase
here perpendicular = 81 feet
base = 59 feet
So Tan%28theta%29 = 81/59= 1.3728
%28theta%29 = 54 deg


Mixture_Word_Problems/341315: Tim and Judy mix two kinds of feed for pedigreed dogs. They wish to make 27 pounds of feed worth $0.26 per pound by mixing one kind worth $0.17 per pound with another worth $0.36 per pound. How many pounds of the cheaper kind should they use in the mix?
1 solutions

Answer 244399 by mananth(12270) About Me  on 2010-09-10 03:43:42 (Show Source):
You can put this solution on YOUR website!
one kind worth $0.17 per pound let this be x lbs.
with another worth $0.36 per pound. this will be 27-x lbs
27 pounds $0.26 per pound
..
0.17*x+0.36(27-x)=27*0.26
0.17x+9.72-0.36x= 7.02
-0.19x = -9.72+7.02
-0.19x=-2.70
x= -2.70/-0.19
= 14.2 lbs.