SOLUTION: to do certain work alone 'A' takes 4 hrs,'B' takes 5 hrs and c takes 6 hrs.how long would A and b together take to do a work which C can do in 4 n half hours?

Question 590971: to do certain work alone 'A' takes 4 hrs,'B' takes 5 hrs and c takes 6 hrs.how long would A and b together take to do a work which C can do in 4 n half hours?
Answer by richwmiller(17219) (Show Source): You can put this solution on YOUR website!
"A" is not the same as "a"
This is math. Be more precise.
[x/4+x/5+x/6=1
x=60/37
Together all three can do the first job in 60/37 hours.
a does 15/37 of the first job
b does 12/37 of the first job
c does 10/37 of the first job]
second job
4.5/6=3/4
c does the job in 3/4 of the time.
3/4 of 4=3
a does the job in 3 hours
3/4 of 5=15/4=3 3/4
b does the job in 3.75 hours
y/3 +y/3.75=1
Together a and b do the second job in 1 2/3 hours

RELATED QUESTIONS
It takes Jonathan 2/3 as long as it takes Juancho to paint a car. If together Jonathan... (answered by ankor@dixie-net.com,josmiceli)

three machines A , B and C take 3 hours to do a job, when working together. Suppose A and (answered by ankor@dixie-net.com)

it takes a painter A 3 hrs to paint a certain area of a hhouse.it takes painter B 5 hrs... (answered by checkley71)

A can do a certain job in 4 hrs, B in 6 hrs, C in 8 hrs. How long will it take to do the... (answered by ptaylor)

Mike and Joe take 3 3/4 hrs to do a job. Joe alone takes 10 hrs to do the same job. How... (answered by stanbon)

Bob takes 2 hours longer to build a table than Fred takes. If they work at the same rate... (answered by richwmiller)

A can do a certain job in 4 hrs, B can do the job in 6 hrs, and C can do the job in 8... (answered by josgarithmetic)

It takes Troy 3 hours to mow his family's large lawn. With his little brother's help, he... (answered by ewatrrr,htmentor)

A can do a certain work in 21 hrs. B can do the task in 28 hrs, C can do the task in 48... (answered by Alan3354)