Fatima can type a project report in 6 hours and Joseph can type it in 12 hours. How long will they take if they split the typing and work at the same time?

Explanation

1. 01

   Fatima's rate = $\frac{1}{6}$ per hour; Joseph's = $\frac{1}{12}$ per hour.

2. 02

   Together: $\frac{1}{6} + \frac{1}{12} = \frac{2+1}{12} = \frac{3}{12} = \frac{1}{4}$ per hour.

3. 03

   So the report takes 4 hours.