Currently, I am 9 times as old as my son. Next year, I will be 7 times as old as my son. How old is my son now?
c = 9s
in one year Creampuff will be c+1 and son will be s+1
c+1 = 7 (s+1) from the first equation we have c/9 = s sub this in to the second equation
c+1 = 7(c/9+1) solve for c
c -7/9 c = 6
2/9 c = 6
c = 27 (s = 3)