Question

When 8 is subtracted from Ollie’s age, the result is the same as subtracting 16 from 3 times his age.

Answer 1

X - Ollie's age

8 is subtracted from Ollie's age = x-8
the result is the same as
subtracting 16 from 3 times his age = 3x-16

$x-8=3x-16 \\ x-3x=-16+8 \\ -2x=-8 \\ x=4$

Ollie is 4 years old.

Answer 2

X - his age

$x-8=3x-16\\ x-3x=-16+8\\ -2x=-8\\ x=4$

He's 4 years old.