4 adults and 3 children cost $40. Two adults and 6 children cost $38 Givens and Assumptions: Let the number of adults be a Let the number of children be c Cost = Price * Quantity We're given 2 equations: 4a + 3c = 40 2a + 6c = 38 We can solve this system of equations 3 ways Substitution Method Elimination Method Cramer's Rule No matter what method we use, we get: a = 7 c = 4