A can complete a work in 20 days and B can do the same work in 30 days. Both A and B can complete the work together in ______ days.

A can complete a work in 20 days and B can do the same work in 30 days. Both A and B can complete the work together in ______ days.

Explanation
To find the number of days A and B take to complete the work together:
A's rate = 1/20 (work per day)
B's rate = 1/30 (work per day)
Combined rate = A's rate + B's rate
= 1/20 + 1/30
= (3 + 2) / 60
= 5/60
= 1/12
So, A and B together can complete the work in 12 days.