Katie, Jackie and Charlie bake cookies. Katie has baked 8 more cookies than Charlie. Jackie has baked 5 more cookies than Katie. Altogether they have baked 72 cookies. How many cookies did Jackie bake?
K = C + 8 → C = K - 8
J = K + 5
J + K + C = 72
(K + 5) + K + (K - 8) = 72
3K - 3 = 72
3K = 75
K = 25
J = 25 + 5 = 30
C = 25 - 8 = 17
