Suppose you have just enough money, in coins, to pay for a gallon of milk priced at $2.40. You have 12 coins, all quarters and dimes. Let q equal the number of quarters and d equal the number of dimes. Which system models the given information?
q - the number of quarters d - the number of dimes
You have 12 coins, all quarters and dimes: q + d = 12
The value of 1 quarter is $0.25. The value of 1 dime is $0.10. Therefore, if you want to pay $2.40 you will have q quarters of value $0.25(0.25q) and d dimes of value $0.10d (0.10d). The second equation is: 0.25q + 0.10d = 2.40
