craig can do a piece of work in 10 days. After he has worked for 2 days, Miko came to help him and together they finished it in 3 days. In how many days could miko alone have done the work

Solution:

Miko: x days

So

(1/10)*2 +3(1/10+1/x) = 1

So

x=6

So Miko can do in 6 days alone