Answer:
18
Step-by-step explanation:
Let's say x is Oscar's age, and y is Vanessa's age.
When Oscar was Vanessa's age, Vanessa was y−(x−y) = 2y−x years old. Oscar is five times older than this:
x = 5 (2y − x)
x = 10y − 5x
6x = 10y
3x = 5y
When Vanessa is Oscar's age, Oscar will be x+(x−y) = 2x−y years old. The sum of their ages will by 72.
2x−y + x = 72
3x − y = 72
Substituting:
5y − y = 72
4y = 72
y = 18
Vanessa is 18. Which means Oscar is 30.
Let's check our answer. When Oscar was 18, Vanessa was 6. Oscar is 5 times older than that (30). When Vanessa is 30, Oscar will be 42, and their ages will add up to 72.
