EXPLANATION
Let's see the facts:
The scale is---> 14 milimeters ----> 5 meters
Width = 42 milimeters
Applying the unitary method, the actual width of the pool is:
[tex]Actual_{}width=42\text{ mm}\cdot\frac{5m}{14\text{ mm}}=15m[/tex]The width of the pool is 15m
