suzy is ten years older than Billy and next year she will be twice as old as Billy. How old is Suzy now? How old is Billy?

Answer 1

present age:
Billy -- x
Suzy -- x+10

next year:
Billy -- x+1
Suzy --- x+11 , but at that time she will be twice as old as Billy ---> x+11 = 2(x+1)

solve for x

Answer 2

Billy is 9 and Suzy is 19