Answer:
9 yr = jennifer's age
18 yr = denise's age
12 yr = anne'e age
Explanation:
Let x = jennifer's age
then 2x = denise's age
and x + 3 = anne'e age
x + 2x + x + 3 = 39
4x + 3 = 39
4x = 36
x = 9 yr = jennifer's age
2x = 18 yr = denise's age
x + 3 = 12 yr = anne'e age