Arithmetic A can complete a piece of work in 6 days and B can complete in 12 days. If A had started that work and worked for 3 days then B joined A. For how many days does B worked?

A can complete a piece of work in 6 days and B can complete in 12 days. If A had started that work and worked for 3 days then B joined A. For how many days does B worked?

A
1 day
B
2 days
C
3 days
D
4 days

Solution:

$A + (A + B) = \frac{3}{6} + (\frac{1}{6} + \frac{1}{12}) D = 1 \frac{3}{12} D = \frac{1}{2} D = 2 B W O R K E D F O R 2 D A Y S$