The sum of Jess, Sam and Mindy’s ages is 42. Jess is younger than Sam, but older than Mindy. Sam is twice as old as Mindy, who is the youngest out of the three by 6 years. If Jess is 15 years old, how old are Sam and Mindy Jess: J Sam: S Mindy: M Jess is younger than Sam, so: J < S Jess in older than Mindy, so: J > M Sam is twice Mindy's age, so S = 2M ----- eq (i) Mindy is the youngest of the 3 by 6 years. Because Jess is the 2nd youngest, Jess is 6 years older than Mindy. Hence, J = M + 6 ----- eq (ii) 15 = M + 6 ---- Substituting 15 (given) for Jess, in eq (ii) 15 - 6 = M 9 = M (Mindy's age) S = 2(9) ------ Substituting 9 for M in eq (i) Sam's age, or S = 18