Question 1077594
Let J represent Jimbob's age and B represent his brother's age:

Jimbob is 3 years older than his brother, so J=B+3
The sum of Jimbob's age and his brother's age is 33, so J+B=33

We now have a system of equations:
J=B+3 (1)
J+B=33 (2)

Substitute (1) into (2):

(B+3)+B=33
2B=30
[B=15]
His brother is 15 years old.

Substitute B=15 into (2)
J+15=33
[J=18]

Hence Jimbob is 18 years old and his brother is 15 years old.