SOLUTION: Al can complete a particular job in 8 hours. Boris can complete the same job in 5 hours. Cody can complete a second job, which requires twice as much work as the first, in 8 hour

Question 400043: Al can complete a particular job in 8 hours. Boris can complete the same
job in 5 hours. Cody can complete a second job, which requires twice as
much work as the first, in 8 hours. If all three people work together on
the larger job for 2 hours, how long, in hours, would it take Al, working
alone, to finish the job?
A 0.8 B 3.0 C 6.8 D 8.0 E 8.8
Answer by ankor@dixie-net.com(22740) (Show Source): You can put this solution on YOUR website!
Al can complete a particular job in 8 hours.
Boris can complete the same job in 5 hours.
Cody can complete a second job, which requires twice as much work as the first, in 8 hours.
If all three people work together on the larger job for 2 hours, how long,
in hours, would it take Al, working alone, to finish the job?
:
The way I understand it, the larger job, which is twice as much work, would require:
Al = 16 hrs alone
Boris = 10 hrs alone
Cody remains at 8 hrs alone
:
The the completed job = 1
Let t = time required by Cody to finish the job
+ + = 1
Multiply by 80
80* + 80* + 80* = 80
Cancel the denominators and you have
5(2) + 8(2) + 10(t+2) = 80
:
10 + 16 + 10t + 20 = 80
:
10t + 46 = 80
:
10t = 80 - 46
10t = 34
t =
t = 3.4 hrs for Cody to finish the job
:
I know this is not one of the given answers, but that's what I get.
:
Check this: Cody works 5.4 hrs total
+ +
.125 + .200 + .675 = 1; confirms our solution

RELATED QUESTIONS
Jake can complete a job in 5 hours while Jerry can complete the same job in 3 hours. How... (answered by deepikabansal)

jake can complete a job in 5 hours while jerry can complete the same job in 3 hours. how... (answered by stanbon)

Jake can complete a job in 5 hours while Jerry can complete the same job in 3 hours... (answered by richwmiller)

Roger can complete a job in 5 hours and Alex can complete the same job in 10 hours. How... (answered by ankor@dixie-net.com)

Jake can complete a job in 5 hours while Jerry can complete the same job in 3 hours. How... (answered by solver91311)

Len can complete a job in 3 hours and Dan can complete the same job in 2 hours. How... (answered by septimus99,Alan3354)

A crew of 6 can complete a job in 8 hours. How many hours would it take a group of 4 to... (answered by rfer,vleith)

Spencer can complete a job in half the amount of time that Zach can complete the job.... (answered by josgarithmetic)

Two printing presses, working together, can complete a job in 2 hours. If one press... (answered by ptaylor)