## A can do a work in 20 days and B in 30 days. In how many days they can complete the work if they work together.

A’s one day’s work = $\frac{1}{20}$

B’s one day’s work = $\frac{1}{30}$

(A + B)’s one day work = $\frac{1}{20}$ + $\frac{1}{30}$ = $\frac{3 + 2}{60}$ = $\frac{5}{60}$ = $\frac{1}{12}$

A and B can complete the work in 12 days