Ke is twice as old as Amy. Seven years ago, the sum of their ages was 31. How old is each person this year

Answer 1

k = 2a
k-7 + a-7 = 31

so,

2a-7 + a-7 = 31
3a-14 = 31
3a = 45
a = 15

So,
Amy is 15 and Ke is 30
7 years ago, 8+23 = 31