Question

A farmer can reap a field in 10 days while his wife can do it in 8 days. if they work together,in how much time can they reap the field?

Answer 1

Work done by farmer = 1/10
work done by farmer's wife = 1/8
If they work together:
= 1/10 + 1/8
= (4 + 5)/40
= 9/40
therefore, they can together reap the field in 40/9 days or 4whole4/9 days...

Answer 2

time taken by farmer to reap the field = 10 days
work done by farmer to reap in 1 day = 1/10 days.
time taken by his wife to complete his work= 8 days
work done by his wife to complete in 1 day = 1/8.
net work done by farmer and his wife in 1 day = 1/10+1/8
4/40+5/40
9/40÷1 = 40/9 = 4 hours 20 minutes.