Question

sarah is twice as old as katie. 10 years ago, the sum of their ages was 23. How old are they now

Answer 1

s = 2 k

s-10 + k-10 = 23

s + k = 43

2 k + k = 43

3 k = 43

k = 43/3 = 14 1/3
s = 28 2/3