James is 15 years older than Sue. In 12 years James will twice Sue's age. How old are James and Sue?

Answer 1

present:
Sue ---- x
James --- x+15

in 12 years:
Sue --- x+12
James --- x+15 + 12 = x + 27

james is twice as old as Sue
x+27 = 2(x+12)
x+27 = 2x + 24
-x = -3
x = 3

Sue is now 3 and James is now 18

check:
in 12 years, Sue will be 15
James will be 30
Will he be twice as old as her ?? YES