P/90 = 4/18
18P = 90*4 [cross-multiplication]
P = 360/18
P = 20
So, answer is P equals to 20
Answer:
True
Step-by-step explanation:

The easiest way I know is to multiply the divisor by different numbers to see how many times it will go into the dividend. multiplying 486 by 2 or three and seeing which one gets closest.
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

Ollie is 4 years old.