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Graphs/398036: graph and check to solve the linear system. 3x+y=5 -x+y=-7 1 solutions
Answer 282050 by mananth(12270) on 2011-01-21 22:27:45 (Show Source):
You can put this solution on YOUR website!graph and check to solve the linear system. 3x+y=5 -x+y=-7
...
3x+5y=5................1
-x+y=-7................2
...
multiply (2) by 3
-3x+3y=-21
add to (1)
8y=-16
y=-2
..
plug value of y in 2
-x-2=-7
-x=-5
x=5
...
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Travel_Word_Problems/398038: a train travels 20 feet in 1/5 seconds, at the same speed how many feet will it travel in three seconds 1 solutions
Answer 282045 by mananth(12270) on 2011-01-21 22:17:30 (Show Source):
You can put this solution on YOUR website!a train travels 20 feet in 1/5 seconds, at the same speed how many feet will it travel in three seconds
20 feet in 1/5 second
so in 1 second it will travel 5 times the distance 5*20=100feet
..
so in 3 seconds it will travel 300 feet
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Geometry_Word_Problems/398013: A rectangular plot of ground having dimensions 21 ft by 24 ft is surrounded by a walk of uniform width. If the area of the walk is 424 ft2, what is its width? 1 solutions
Answer 282043 by mananth(12270) on 2011-01-21 22:13:55 (Show Source):
You can put this solution on YOUR website!A rectangular plot of ground having dimensions 21 ft by 24 ft is surrounded by a walk of uniform width. If the area of the walk is 424 ft2, what is its width?
..
area of ground = 21*24=504 ft^2
...
area of walk = 424 ft^2
..
let width of walk be x
..
width of total area = 21+2x
length of total area = 24+2x
..
Area of total area = (21+2x)(24+2x)
Total Area = 504+90x+4x^2
..
4x^2+90x+504-504 = 424
4x^2+90x-424=0
Find the roots of the equation by quadratic formula
a= 4 , b =90 , c = -424 .
b^2-4ac=14884

x1= 4
x2= negative so ignore
walk width = 4 feet
...
m.ananth@hotmail.ca
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Miscellaneous_Word_Problems/398019: Amount of an investment. The amount of an investment
of P dollars for t years at simple interest rate r is given by
A = P + Prt.
a) Rewrite this formula by factoring out the greatest
common factor on the right-hand side.
b) Find A if $8300 is invested for 3 years at a simple
interest rate of 15%. 1 solutions
Answer 282035 by mananth(12270) on 2011-01-21 21:52:48 (Show Source):
You can put this solution on YOUR website!Amount of an investment. The amount of an investment
of P dollars for t years at simple interest rate r is given by
A = P + Prt.
a) Rewrite this formula by factoring out the greatest
common factor on the right-hand side.
b) Find A if $8300 is invested for 3 years at a simple
interest rate of 15%.
...
A=P+Prt
A=P(1+rt)
A=8300(1+0.15*3)
A=8300(1.45)
A=$ 12035
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Geometry_Word_Problems/398015: A farmer plans to enclose a rectangular region, using part of his barn for one side and fencing for the other three sides. If the side parallel to the barn is to be twice the length of an adjacent side, and the area of the region is to be 98 ft2, how many feet of fencing should be purchased? 1 solutions
Answer 282033 by mananth(12270) on 2011-01-21 21:47:13 (Show Source):
You can put this solution on YOUR website!A farmer plans to enclose a rectangular region, using part of his barn for one side and fencing for the other three sides. If the side parallel to the barn is to be twice the length of an adjacent side, and the area of the region is to be 98 ft2, how many feet of fencing should be purchased?
...
let the adjacent side be x ft.
the other side will be 2x
...
The area = L*W
Area = x*2x=2x^2
2x^2=98
x^2=49
x=7 feet
..
the three sides to be fenced will be x+x+2x=4x
x=7
so 7*4 = 28 feet of fencing will be required.
...
m.ananth@hotmail.ca
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Linear-equations/398022: how do you this problem so can graph it 2x+y=1 1 solutions
Answer 282031 by mananth(12270) on 2011-01-21 21:37:45 (Show Source):
You can put this solution on YOUR website!how do you this problem so can graph it 2x+y=1
..
2x+y=1
y=-2x+1
..
generate values for y from various values of x
x=0,y=1........(0,1)
y=0,x=1/2.......(1/2,0)
..
plot these points and draw the line graph.
...
check to see whether the slope is -2 from the graph.
...
m.ananth@hotmail.ca
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Rational-functions/398027: Find a Polynomial for the perimeter and for the area. (Simplify, do not factor)
N+2
n
The perimeter is
The area is
1 solutions
Answer 282021 by mananth(12270) on 2011-01-21 21:17:26 (Show Source):
You can put this solution on YOUR website!length = n+2
width = n
....
Perimeter = 2*(L+W)\
Perimeter = 2(n+n+2)
=2*(2n+2)
if n is not equal to N ( due a typo)
then 2*(n+N+2)units
..
Area = L*W
n(N+2)sq.units
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Volume/397189: Harry has a large number of cubes, all with edges 3cm long.What is the greatest number of these cubes that he could fit into
a) A Cubical box with all its internal edges 12cm long.
b) A box in the shape of a cuboid with internal dimensions 17cm by 10cm by 8cm. 1 solutions
Answer 281573 by mananth(12270) on 2011-01-20 08:34:54 (Show Source):
You can put this solution on YOUR website!Harry has a large number of cubes, all with edges 3cm long.What is the greatest number of these cubes that he could fit into
a) A Cubical box with all its internal edges 12cm long.
b) A box in the shape of a cuboid with internal dimensions 17cm by 10cm by 8cm.
volume of bigger cube/volume of smaller cube = number of cubes
..
side = 12
v= 12*12*12
=1728cm^3
...
volume of small cube = 3*3*3=27cm^3
1728/27
=64 small cubes
..
Volume of cuboid = 17*10*8
V=1360 cm^3
1360/27
50.3
50 small cubes can be placed
,
m.ananth@hotmail.ca
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Travel_Word_Problems/397197: Beth was required to make a cross-country flight in training for her pilot's license. When she flew from her home airport, a steady 30 miles per hour wind was behind her, and the trip took 5 hours. When she returned against the wind, the flight took 7 hours. Find the plane's speed in still air and the distance traveled each way. 1 solutions
Answer 281569 by mananth(12270) on 2011-01-20 08:18:24 (Show Source):
You can put this solution on YOUR website!Beth was required to make a cross-country flight in training for her pilot's license. When she flew from her home airport, a steady 30 miles per hour wind was behind her, and the trip took 5 hours. When she returned against the wind, the flight took 7 hours. Find the plane's speed in still air and the distance traveled each way.
plane's speed = x mph
..
with wind speed = x+30
against wind = x-30
...
d=rt. d is same so equate the distance
5(x+30)=7(x-30)
5x+150=7x-210
7x-5x=210+150
2x=360
/2
x= 180 mph speed in still air
..
m.ananth@hotmail.ca
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Mixture_Word_Problems/397207: A collection of nickels and dimes adds up to $5.60. If the ratio of dimes to nickels is 3:2, how many of each coin is there? 1 solutions
Answer 281567 by mananth(12270) on 2011-01-20 08:11:01 (Show Source):
You can put this solution on YOUR website!nickels to dimes = 3/2
let the common factor be x
3x/2x=
5(3x)+10(2x)=560
15x+20x=560
35x=560
x= 560/35
x=16
...
nickels = 3*16=48
Dimes= 2*16=32
..
CHECK
48*5+10*32=240+320=560
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Linear-equations/397211: how would I solve x/2 + x/3= 3/4 I know the least common denominator is 12 but I am having trouble working the problem out. 1 solutions
Answer 281564 by mananth(12270) on 2011-01-20 07:57:59 (Show Source):
You can put this solution on YOUR website!how would I solve x/2 + x/3= 3/4 I know the least common denominator is 12 but I am having trouble working the problem out.
.
x/2 + x/3= 3/4
LCD =12
multiply each fraction by 12
12x/2 +12x/3=36/4
6x+4x=9
10x=9
divide by 10
x= 9/10
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Numbers_Word_Problems/397208: The sum of one-half, one-third and one-fourth of a number exceeds the number by 12. The number is 1 solutions
Answer 281561 by mananth(12270) on 2011-01-20 07:49:55 (Show Source):
You can put this solution on YOUR website!The sum of one-half, one-third and one-fourth of a number exceeds the number by 12. The number is
let the number be x
x/2 +x/3+x/4 = x+12
...
LCD = 12
(6x+4x+3x)/12=x+12
13x= 12(x+12)
13x=12x+144
13x-12x=144
x= 144
..
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test/396592: The sum of 3 integers is 123. The second number is two more than twice the first number. The third number is five less than the product of three and the first number. Find the three numbers 1 solutions
Answer 281279 by mananth(12270) on 2011-01-19 01:33:37 (Show Source):
You can put this solution on YOUR website!The sum of 3 integers is 123. The second number is two more than twice the first number. The third number is five less than the product of three and the first number. Find the three numbers
...
let the integers be x, y, z
..
x+y+z=123...........................1
..
y=2x+2...............................2
...
z=3x-5...............................3
...
plug value of y & z in equation (1)
x+2x+2+3x-5 =123
6x-3=123
6x=126
/6
x= 21
y= 2x+2= 44
z=58
..
21+44+58=123
...
m.ananth@hotmail.ca
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Rate-of-work-word-problems/396577: Working together, two pipes can fill the tank in 2 hours and 6 minutes. Working alone, the larger pipe fills the tank in 4 hours less time than the smaller on. How long does the larger pipe take? 1 solutions
Answer 281278 by mananth(12270) on 2011-01-19 01:09:01 (Show Source):
You can put this solution on YOUR website!Working together, two pipes can fill the tank in 2 hours and 6 minutes. Working alone, the larger pipe fills the tank in 4 hours less time than the smaller on. How long does the larger pipe take?
6 minutes=6/60 = 1/10 hours
both pipes 2 1/10 hours= 23/10 hours
they do 10/23 of the filling in 1 hour
.....
smaller pipe takes x hours
it does 1/x of filling in 1 hour
....
larger pipe takes x-4 hours
it does1/(x-4) of the job in 1 hour
...
1/x + 1/(x-4)= 10/23
LCD = x(x-4)
(x-4+x)/x(x-4)=10/23
cross ultiply
23(2x-4)=10x(x-4)
46x-92=10x^2-40x
10x^2-86x+92=0
/2
5x^2-43x+46=0
solve using quadratic formula
Find the roots of the equation by quadratic formula
a= 5 , b = -43 , c =46
b^2-4ac= 929 .

7.3 hours
...

x2= (43-sqrt(929))/(10)
x2=1.25 this is not possible since larger pipe takes four hours less.
So larger pipe takes 7.34-4 = 3.3 hours
m.ananth@hotmail.ca
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Mixture_Word_Problems/396586: A chemist wants to dilute a 30% phosphoric acid solution to a 15% solution. He needs 10 liters of the 15% solution. How many liters of the 30% solution and water must the chemist use? 1 solutions
Answer 281276 by mananth(12270) on 2011-01-19 00:40:59 (Show Source):
You can put this solution on YOUR website!A chemist wants to dilute a 30% phosphoric acid solution to a 15% solution. He needs 10 liters of the 15% solution. How many liters of the 30% solution and water must the chemist use?
30% solution ------------- x liters
0%(water)-----------------------10-x liters
15%------------------------10 liters
...
30*x+0=15*10
30x=150 liters
/30
x= 5 liters of water.
5 liters of 30% solution
..
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Evaluation_Word_Problems/396549: a freight train leaves the station 2 hours before a passenger train. There are two trains are traveling in the same direction on parallel tracks. If the rate of the passenger train is 11 mph faster than the Freight train, how fast is each train traveling if the passenger train passes the freight train in 10 hours? 1 solutions
Answer 281275 by mananth(12270) on 2011-01-18 23:18:02 (Show Source):
You can put this solution on YOUR website!a freight train leaves the station 2 hours before a passenger train. There are two trains are traveling in the same direction on parallel tracks. If the rate of the passenger train is 11 mph faster than the Freight train, how fast is each train traveling if the passenger train passes the freight train in 10 hours?
..
freight train = x mph
passenger train = x+11 mph
...
freight train time = 10 +3 = 13 hours
passanger train = 10 hours
..
distance same. because they meet
..
13x=10(x+11)
13x=10x+110
13x-10x=110
3x= 110
/3
x= 36.66 mph speed of freight train
passenger train speed = 36.66 +11 = 47.66 mph
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Rate-of-work-word-problems/396484: Please show me how to solve this problem. I am sure that there is an equation to use but I do not know where to start.
A backyard pool is being drained. The pool contains 9925 gallons of water. At 9am, Drain 1 is opened which drains at 175 gallons every 15 minutes. At 10am, Drain2 is opened (Drain 1 continues draining, too) and it drains 450 gallons every 30 minutes. At what time will the pool contain 0 gallons of water?
THANK YOU! 1 solutions
Answer 281272 by mananth(12270) on 2011-01-18 22:30:53 (Show Source):
You can put this solution on YOUR website!A backyard pool is being drained. The pool contains 9925 gallons of water. At 9am, Drain 1 is opened which drains at 175 gallons every 15 minutes. At 10am, Drain2 is opened (Drain 1 continues draining, too) and it drains 450 gallons every 30 minutes. At what time will the pool contain 0 gallons of water?
THANK YOU!
...
let the total time to drain be x
..
Drain 1 = 700 gallons /h
Drain 2 = 900 gallons/h
...
Drain 1 is open for x hours
so it drained 700x gallons
..
Drain 2 is open for (x-1) hours
so it drains 900(x-1) gallons
...
700x+900(x-1)=9925
700x+900x-900=9925
1600x=9925+900
1600x= 10825
/2500
x= 6.765 hours
x= 6hours 46 minutes
Time it will empty = 3.46 pm
...
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Graphs/396501: Help please
Find two consecutive integers that have a product of 20 1 solutions
Answer 281253 by mananth(12270) on 2011-01-18 21:49:28 (Show Source):
You can put this solution on YOUR website!let one integer be x
the other will be x+1
..
x(x+1)=20
x^2+x=20
-20
x^2+x-20=0
x^2+5x-4x-20=0
x(x+5)-4(x+5)=0
(x+5)(x-4)=0
x= -5 OR 4
-5+1=-4
(-5,-4)
...
..
4+1=5
(4,5)
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Linear_Equations_And_Systems_Word_Problems/396075: Joe and Sam have received walkie-talkies for their birthdays. If they leave from the same point at the same time, Joe walking north at 2.5 mph and Sam walking east at 3 mph, how long will they be able to talk to each other if the range of the walkie-talkies is 4 mi. Round your answer to the nearest minute. 1 solutions
Answer 281050 by mananth(12270) on 2011-01-18 05:03:52 (Show Source):
You can put this solution on YOUR website!Joe and Sam have received walkie-talkies for their birthdays. If they leave from the same point at the same time, Joe walking north at 2.5 mph and Sam walking east at 3 mph, how long will they be able to talk to each other if the range of the walkie-talkies is 4 mi. Round your answer to the nearest minute.
..
Joe- 2.5 mph
Sam - 3mph
time they walk is the same
let the time be t
2.5t -- joe distance
3t ----- same distance
..
they are walking at right angles
use pythagoras theorem
(2.5t)^2 +(3t)^2=4^2
6.25t+9t=16
15.25t=16
t = 16/15.25
time = 1.08 hours
...
m.ananth@hotmail.ca
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