Question 285950
d = Derek's age
s = Sarah's age
d = 4s  :: Derek is 4 times as old as Sarah
.
3 years ago...
Derek's age = d-3
Sarah's age = s-3
.
The sum of their ages was 44...
.
(d-3)+(s-3) = 44
.
Substitute d = 4s...
.
(4s-3) + (s-3) = 44
.
And there you go...