Answer:
The age of the fourth boy = 38
Step-by-step explanation:
We can find the age of the fourth boy by finding out the difference between the total of 4 boys and the total of the 1st three boys:
[tex]\begin{aligned}\\\text{total of 4 boys}&=\text{total of 3 boys + 4th boy}\\4\times 32&=3\times 30+\text{4th boy}\\\text{4th boy}&=128-90\\&=38\end{aligned}[/tex]