Lalremsiami can weave a shawl in 5 days and her apprentice Anjali in 20 days. Weaving together on the same loom, how many days will the shawl take?

Explanation

1. 01

   Rates: $\frac{1}{5}$ and $\frac{1}{20}$ per day.

2. 02

   Together: $\frac{4}{20} + \frac{1}{20} = \frac{5}{20} = \frac{1}{4}$ per day, so 4 days.