Let x be the youngest; then the oldest is 3x years old. You have then this equation for the average age= 16. It implies 4x = 4*16 - 10 - 22 = 32 x = 32/4 = 8. ANSWER. The youngest child in the family is 8 years old.
YOUNGEST j MIDDLE1 10 MIDDLE2 22 OLDEST 3j Average 16