tim sells three pepperoni pizzas for every one cheese pizza. this means he sells three times the amount of pepperoni compared to cheese
x = # cheese pizzas
x*3 = # pepperoni pizzas
x + 3x = 64
4x = 64
x = 16 cheese pizzas
64 - 16 = 48 pepperoni pizzas
he sells 16 cheese pizzas and 48 pepperoni pizzas
price of cheese: $10
price of pepperoni: $15
10(16) + 15(48) = 160 + 720 = $880
hope this helps