SOLUTION: It takes Ralph 14 hours to paint a fence alone. Lisa can do the same job in 18 hours. If Ralph paints alone for 45 minutes before Lisa begins helping, how long must they work toget
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-> SOLUTION: It takes Ralph 14 hours to paint a fence alone. Lisa can do the same job in 18 hours. If Ralph paints alone for 45 minutes before Lisa begins helping, how long must they work toget
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Question 906025: It takes Ralph 14 hours to paint a fence alone. Lisa can do the same job in 18 hours. If Ralph paints alone for 45 minutes before Lisa begins helping, how long must they work together to finish painting the fence? Give your answer as a simplified fraction. Found 2 solutions by richwmiller, lwsshak3:Answer by richwmiller(17219) (Show Source):
You can put this solution on YOUR website! .75/14+x/14+x/18=1
.75/14+9x/126+7x/126=1
.75/14+16x/126=1
8x/63=14/14-.75/14
8x/63=13.25/14
14*8x=63*13.25
112x=834.75
x=834.75/112
or
x = 7.45313
You can put this solution on YOUR website! It takes Ralph 14 hours to paint a fence alone. Lisa can do the same job in 18 hours. If Ralph paints alone for 45 minutes before Lisa begins helping,
Give your answer as a simplified fraction.
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1/14=Ralph's work rate
1/18=Lisa's work rate
1/14+1/18=18/252+14/252=32/252=8/63=work rate working together
let x=time working together to finish the job
45 min=3/4 hr
..
(3/4)(1/14)+x(8/63)=1 (100% of job)
3/56+8x/63=1
cd:56*63=3528
189+448x=3528
448x=3339
=3339/448≈7.45
how long must they work together to finish painting the fence?≈7.45 hrs
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