Question 701892
jill = x years
jack = x+4

hence after 7 years
jill= x + 7
jack= x+4+7
    = x+11

so Jack= x+11
and jill= x+7

The sum of both must equal 60 
x+11+x+7=60

Solve for x
2x+18=60
2x=42
x=21

Jill is 21