Amy = x Betty = y Carl = z x + y = 29 x + z = 27 y + z = 22 y = 29 - x z = 27 - x 29 - x + 27 - x = 22 -2x + 56 = 22 -2x = - 34 x = 17 y = 12 z = 10 Oldest child is Amy (17) and youngest child is Carl (10) 17 - 10 = 7 The difference between oldest child and youngest child is 7 years.