Answer:
Brett is 13 years old.
Explanation:
Both ages are in terms of Julie's age, so let j = Julie's age.
Julie's age = j
Sal's age = 3j + 4
Brett's age = 2j - 5
Sum of ages = 53
j + 3j + 4 + 2j - 5 = 53
6j - 1 = 53
6j = 54
j = 9
Julie is 9 years old.
Brett's age:
2j - 5 = 2(9) - 5 = 18 - 5 = 13
Answer: Brett is 13 years old.