Question

1. Bill wants to buy coffee for his class at the LePhooPhoo Coffee Shop. He needs to buy 30 cups of coffee. The large coffees cost $4 and the medium coffees cost $3. If he spends $102 on coffee, how many of each size coffee did he buy?​

Answer 1

large = 12

medium = 18

Explanation:

L + M = 30 => L = 30-M

4L+3M =102

substitute : L with M

=> 4(30-M)+3M =102

120-4M+3M = 102

- M = 102-120

-M = -18

=========> M = 18, L = 12