A contractor plans to lay a road with 30 workers in 40 days. After 16 days, 10 more workers join. In how many days in all is the road finished?

Explanation

1. 01

   Total work = $30 \times 40 = 1200$ worker-days.

2. 02

   In 16 days: $30 \times 16 = 480$ worker-days, leaving 720.

3. 03

   Now 40 workers: $720 \div 40 = 18$ more days.

4. 04

   Total = $16 + 18 = 34$ days.