When john and Marsha worked together, they finished a job in ten days. But when she joined him only after he worked for 7 days, they finished the same job in 5 more days. In how many days can each of them finish the job alone?

Question

dumbcow · Answer

Similar to last problem:

The rate they work together is T, the rate that john works is J
10T =  7J + 5T

T = (7/5)J

10(7/5)J = 14J
takes John 14 days by himself

anonymous · Answer

how about marsha?

dumbcow · Answer

Well if M is rate that marsha works

T = J + M = 7/5J
-> M = (2/5)J

14J = X*M
14J = X*(2/5)J
X = 14(5/2) = 35

it takes marsha 35 days