$\left[\right.$ Arithmetic. Mental calculation, etc.] $\left[\begin{array}{l}\text { Work problems. }\end{array}\right]$

Three diggers dug three holes in three hours. How many holes will six diggers dig in five hours?
First, calculate how many pits 6 diggers will dig in 3 hours.

## Solution

Six diggers in 3 hours will dig $2 \cdot 3=6$ pits. And in 5 hours, they will dig $5 / 3 \cdot 6=10$ pits.

## Answer

10 pits.