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The ToTal value of The coins in The bank is $3.70 . If the dimes were quarters and quarters were dimes, the total value of the coIns would be $2.95 . Find the number of quarters in the bank. 1 solutions
Answer 356399 by mananth(12270) on 2011-12-14 19:31:03 (Show Source):
You can put this solution on YOUR website!dimes = x numbers
quarters = y numbers
convert $ to cents
10x+25y=370
25x+10y=295
dimes x
Quarters y
10 x + 25 y = 370 .............1
25 x + 10 y = 295 .............2
Eliminate y
multiply (1)by 2
Multiply (2) by -5
20 x 50 y = 740
-125 x + -50 y = -1475
Add the two equations
-105 x = -735.00
/ -105
x = 7
plug value of x in (1)
10 x + 25 y = 370
70 + 25 y = 370
25 y = 370 -70
25 y = 300
y = 12
dimes = 7
Quarters= 12
m.ananth@hotmail.ca
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Percentage-and-ratio-word-problems/547100: aling martha invested part of her P20,000 at 8% interest and the remaining at 7%. If the total earnings for the investment is P1520, how much did she invest at 8%? 1 solutions
Answer 356261 by mananth(12270) on 2011-12-14 09:18:26 (Show Source):
You can put this solution on YOUR website!Fund A 8.00% per annum ---x
Fund B 7.00% per annum ---y
x + y= 20000 ------------------------1
8.00% x + 7.00% y= = $1,520.00
Multiply by 100
8 x + 7 y= = $152,000.00 --------2
Multiply (1) by -8
we get
-8 x -8 y= = -160000.00
Add this to (2)
0 x -1 y= = -P8,000.00
divide by -1
y = P8,000.00 investment at 7.00%
Balance P12,000.00 investment at 8.00%
CHECK
$12,000.00 --------- 8.00% ------- P960.00
$8,000.00 ------- 7.00% ------- P560.00
Total -------------- P1,520.00
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Linear-equations/547145: find the equation of the line that is perpendicular to 9x-3y=-2 and contains the point (0,4). i know the answer is y=-1/3x+4 but i don't know how to get it. 1 solutions
Answer 356259 by mananth(12270) on 2011-12-14 09:07:14 (Show Source):
You can put this solution on YOUR website!9 x -3 y = -2
Find the slope of this line
-3 y = -9 x -2
Divide by -3
y = 3 x + 0.67
Compare this equation with y=mx+b, m= slope & b= y intercept
slope m = 3
The slope of a line perpendicular to the above line will be the negative reciprocal
m1*m2=-1
The slope of the required line will be - 1/3
m= - 1/3 ,point ( 0 , 4 )
Find b by plugging the values of m & the point in
y=mx+b
4 = 0.00 + b
b= 4
m= - 1/3
The required equation is y =- 1/ 3x+4
m.ananth@hotmail.ca
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Travel_Word_Problems/547099: At his usual rate a man rows 15 miles downstream in five hours less time than it takes him to return. If he doubles his usual rate, the time downstream is only one hour less than the time upstream. Find the rate of the streams current? 1 solutions
Answer 356254 by mananth(12270) on 2011-12-14 08:49:38 (Show Source):
You can put this solution on YOUR website!let speed of boat be x
speed of current be y
downstream speed = x+y
upstream speed = x-y
15/(x-y) -15/(x+y)=5
LCD = (x+y)(x-y)
multiply by the LCD
15(x+y)-15(x-y)=5(x^2-y^2)
15x+15y-15x+15y=5(x^2-y^2)
30y=5(x^2-y^2)
----------------
Speed is doubled
downstream speed = 2x+y
upstream speed = 2x-y
15/(2x-y)-15/(2x+y)=1
LCD = (2x+y)(2x-y)
multiply by the LCD
15(2x+y)-15(2x-y)=4x^2-y^2
30x+15y-30x+15y=4x^2-y^2
30y=4x^2-y^2
equate 30y from both equations
5x^2-5y^2=4x^2-y^2
x^2-4y^2=0
x=2y
substitute x=2y in
15/(x-y) -15/(x+y)=5
15/(2y-y)-15/(2y+y)=5
15/y-15/3y=5
45-15=15y
30=15y
30/15=y
y=2 the current speed
x=4 mph boat speed
m.ananth@hotmail.ca
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Exponents/547136: if x2+y2=85
and xy=9
what is (x+y)2
*the 2 behind means to the second power i couldn't get it 2 show properly 1 solutions
Answer 356246 by mananth(12270) on 2011-12-14 08:21:50 (Show Source):
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Radicals/547137: use the quadratic formula to solve the following equations
(r-2)(r+6)=11
simplify your answer. type an exact answer using radicals as needed. use integers or fractions for any numbers in the expression. use a comma to seperate answers as needed.
1 solutions
Answer 356243 by mananth(12270) on 2011-12-14 08:16:36 (Show Source):
You can put this solution on YOUR website!(r-2)(r+6)=11
r(r+6)-2(r+6)+11=0
r^2+6r-2r-12+11=0
r^2+4r-1=0
Find the roots of the equation by quadratic formula
a= 1 ,b= 4 ,c= -1
b^2-4ac= 16 + 4
b^2-4ac= 20
x1=( -4 + 4.47 )/ 2
x1= 0.24
x2=( -4 -4.47 ) / 2
x2= -4.24
you can also work it out in fractions
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Radicals/547134: solve by completing the square
x^2-6x-4=0
simplify your answer. type an exact answer using radicals as needed. use integers or fractions for any numbers in the expression. use a comma to seperate answers as needed.
1 solutions
Answer 356242 by mananth(12270) on 2011-12-14 08:12:15 (Show Source):
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Travel_Word_Problems/547092: A bucket of water is brought up from a well 9.68 m deep by a rope which winds round a drum 22 cm in diameter. How many turns of the handle are required to bring up a bucket from the bottom of the well? 1 solutions
Answer 356213 by mananth(12270) on 2011-12-14 04:47:13 (Show Source):
You can put this solution on YOUR website!drum diameter = 22 cm = 0.22 m
radius = 0.22/2=0.11 m
height = 9.68 m
2 * pi * 0.11=0.691 m
Number of turns = 9.68/0.691
= 14 turns
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Travel_Word_Problems/547041: a train travels 100km in the same time that a plane covers 450 km. if the speed of the plane is 30km per hr less than 5 times the speed of the train , find both speeds.. 1 solutions
Answer 356210 by mananth(12270) on 2011-12-14 04:31:29 (Show Source):
You can put this solution on YOUR website!train speed =x
distance =180
plane speed = 5x-30
distance = 450
t=d/r
100/x = 450/(5x-30)
time for both is same
cross multiply
100(5x-30)=450x
500x-3000=450x
500x-450x=3000
50x=3000
/50
x=60 mph speed of car
speed of plane = 5x-30
=5*60-30
=300-30
=270 mph speed of plane
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Linear_Equations_And_Systems_Word_Problems/547085: Chemistry. E-Chem Testing has a solution that is 80% base and another that is 30% base. A technician needs 150 L of a solution that is 62% base. The 150 L will be prepared by mixing the two solutions on hand. How much of each should be used? 1 solutions
Answer 356205 by mananth(12270) on 2011-12-14 04:07:22 (Show Source):
You can put this solution on YOUR website!percent ---------------- quantity
Base I 80 ---------------- x L
Base II 30 ------ 150 - x L
Mixture 62.00% ---------------- 150
80x+30(150-x)=62*150
80x+4500-30x=9300
80x-30x =9300-4500
50x=4800
/ 50
x =96L 80.00% Base I
54L 30.00% Base II
m.ananth@hotmail.ca
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Travel_Word_Problems/547081: two cars leave delhi at the same time travelling in opposite directions. if the average speed of one car is 5 km/hr more than that of the other and they are 425 km apart at the end of 5 hrs, what is the average speed of each? 1 solutions
Answer 356199 by mananth(12270) on 2011-12-14 02:43:00 (Show Source):
You can put this solution on YOUR website!Car I x kmph
Car II x+ 5 kmph
..
They are moving away from each other
So add up their speed.
combined speed = x+x+5
(2x+5)
Time = 5 hours
Distance = 425 km
Distance = speed * time
(2x+5 )* 5 = 425
10 x + 25 = 425
10 x = 425 + -25
10 x = 400
/ 10
x= 40 kmph Car I
Car II 40 + 5 = 45 kmph
m.ananth@hotmail.ca
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Travel_Word_Problems/547045: a cheetah was timed running 200 yards in 6 seconds. What was its average speed in miles per hour?
I am a mom trying to help my daughter with her math homework. Not sure where to begin with this. Do I divide 200 by 6? but then what? I need help!! Could you show me what the problem should look like? Thanks!! Amy 1 solutions
Answer 356196 by mananth(12270) on 2011-12-14 02:36:51 (Show Source):
You can put this solution on YOUR website!a cheetah was timed running 200 yards in 6 seconds. What was its average speed in miles per hour?
you must first do the conversion from yards/second to miles/hour.
Then your problem is solved.
1 yard = 3 feet
600 yards=1800feet
1800 feet in 6 seconds
so in 1 second the cheetah runs
1800/6 = 300 feet /second
....
convert 300 feet/second to miles /hour
1 mile = 5280 feet
1 second = 1/3600 hour ( 3600 seconds ,ake an hour)
300 feet = 300/5280 miles
1 second = 1/3600 hour
=204.5 mph
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Finance/547066: how can 56000 be invested part at 4% annual simple interest ant the remainder at 10% annual simple interest so that the interest erned by the two accounts is equal at the end if the year 1 solutions
Answer 356194 by mananth(12270) on 2011-12-14 02:24:57 (Show Source):
You can put this solution on YOUR website!x+y=56000
x@ 4%
y@10%
0.04x = 0.1y
0.04x-0.1y=0
x+y=56000 .............1
0.04x-0.1y=0 .............2
Eliminate y
multiply (1)by 1
Multiply (2) by 10
1 x 1 y = 56000
0.4 x + -1 y = 0
Add the two equations
1.4 x = 56000.000
/ 1.4
x = 40000
plug value of x in (1)
1 x + 1 y = 56000
40000 + 1 y = 56000
1 y = 56000 -40000
1 y = 16000
y = 16000
4000@4%
16000@10%
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Mixture_Word_Problems/547076: how many pounds of peanuts at php 80.00 per pound should be added to 200 pounds of cashew nuts at php 200.00 per pound of the mixture is to be worth php 120.00 per pound? 1 solutions
Answer 356193 by mananth(12270) on 2011-12-14 02:19:59 (Show Source):
You can put this solution on YOUR website! --------price ---------------- quantity
cashew 200 ---------------- 200 lb
peanuts 80 ---------------- x lb
Mixture 120 ---------------- 200 + x lb
200*200 +80x=120(200+x)
40000+80x=24000 +120x
80x+(-120x)=24000 -(-40000)
-40 x = -16000
/-40
x=400
400 lb of peanuts
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Linear-systems/547050: 2y=2x-2
x=y+1 1 solutions
Answer 356191 by mananth(12270) on 2011-12-14 02:12:21 (Show Source):
You can put this solution on YOUR website!-2 x + 2 y = -2 .............1
1 x -1 y = 1 .............2
Eliminate y
multiply (1)by 1
Multiply (2) by 2
-2 x 2 y = -2
2 x + -2 y = 2
Add the two equations
0 x = 0
there are infinite solutions
if you draw the graph of the lines the lines coincide.
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Expressions-with-variables/547071: Solve using two equations in two variables.
Kathleen invested $5000, some at 6% and the rest at 5%. Her annual income from the investments is $280. How much is invested at 5%? 1 solutions
Answer 356190 by mananth(12270) on 2011-12-14 01:42:46 (Show Source):
You can put this solution on YOUR website!Fund A 5.00% per annum ---x
Fund B 6.00% per annum ---y
x+y=5000 ------------------------1
5.00% x + 6.00% y= = $280.00
Multiply by 100
5x+6y= $28,000.00 --------2
Multiply (1) by -5
we get
-5x-5y= -25000.00
Add this to (2)
y =$3,000.00 investment at 6.00%
Balance $2,000.00 investment at 5.00%
CHECK
$2,000.00 --------- 5.00% ------- $100.00
$3,000.00 ------- 6.00% ------- $180.00
Total -------------- $280.00
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Expressions-with-variables/547075: A grocer makes a natural breakfast cereal by mixing oat cereal costing $2 per kilogram with dried fruits costing $9 per kilogram. How many kilograms of each are needed to make 60 kg of cereal costing $3.75 per kilogram? 1 solutions
Answer 356189 by mananth(12270) on 2011-12-14 01:36:20 (Show Source):
You can put this solution on YOUR website!price ---------------- quantity
Oat cereal 2 ---------------- x lb
dry fruits 9 ------ 60 - x lb
Mixture 3.75% ---------------- 60
2 x + 9 ( 60 - x ) = 3.75 * 60
2 x + 540 - 9 x = 225
2 x - 9 x = 225 - 540
-7 x = -315
/ -7
x=45
45 lb $ 2.00 Oat cereal
15 lb $ 9.00 dry fruits
m.ananth@hotmail.ca
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Linear-equations/546864: Find the slope and y-intercept of the line that is perpendicular to y=1/3x-3 and passes through the point (-4, 3).
1 solutions
Answer 356130 by mananth(12270) on 2011-12-13 20:11:07 (Show Source):
You can put this solution on YOUR website! y = 1/ 3 x + -3
Compare this equation with y=mx+b, m= slope & b= y intercept
slope m = 1/3
The slope of a line perpendicular to the above line will be the negative reciprocal -3
m1*m2=-1
The slope of the required line will be -3
m= -3 ,point ( -4 , 3 )
Find b by plugging the values of m & the point in
y=mx+b
3 = 12.00 + b
b= -9
m= -3
The required equation is y =-3x-9
m.ananth@hotmail.ca
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Graphs/546903: write an equation of the line that passes through the point (3,-2) with slope of 3 1 solutions
Answer 356126 by mananth(12270) on 2011-12-13 20:05:58 (Show Source):
You can put this solution on YOUR website!m= 3
Plug value of the slope and point ( 3,-2 ) in
Y = m x + b
-2.00 = 9 + b
b= -2 - 9
b= -11
So the equation will be
Y = 3 x -11
m.ananth@hotmail.ca
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