Answer:
Jenny's age = 8 yr
Sam's age = 17 yr
Explanation:
Let x = Jenny's age now
then x + 9 = Sam's age now
x - 5 = Jenny's age 5 years ago
x + 9 - 5 = x + 4 = Sam's age 5 years ago
4(x - 5) = x + 4
4x - 20 = x + 4
3x = 24
x = 8 = Jenny's age now
x + 9 = 8 + 9 = 17 Sam's age now
Check: 5 yrs ago Jenny was 3 and Sam was 12
4(3) = 12, so the answer is correct.