Question

11. Three persons A, B and C working together can plough a field in 32 days. The persons
A and C together can do it in 16 days. If A alone can do it in 24 days, how long would A and B working together take to plough the field?​

Answer 1

Answer:

Three person A B and C working together can plough a field in 32÷3 days. The persons A and C together do it in 16 days. If A alone can do it in 24 days, how long would A and B working together take to plough the field?

Solution: A, B and C plough (3/32)nd of the field in 1 day.

A and C plough (1/16)th of the field in 1 day.

A, alone ploughs (1/24)th of the field in 1 day.

Hence, C, alone ploughs (1/16)-(1/24) = (3–2)/48 = (1/48)th of the field in 1 day.

And, B alone ploughs (3/32)-(1/16) = (3–2)/32 = (1/32)th of the field in 1 day.

Or A and B plough (1/24) +(1/32) = (4+3)/96 = (7/96)th of the field in 1 day.

Thus A and B together plough the field in 96/7 or 13 and 5/7 days. Answer.