Question

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 give the field.

Answer 1

I guess the answer will be 18

Answer 2

farmer reap the field in a day = 1/10
his wife reap the field in a day = 1/8

both reap the field = 2/18 = 9 days