Problema Solution
Ben ordered 19 pizzas for party. He ordered 3 types...cheese, pepperoni and supreme. Cheese pizza costs $6 each, pepperoni $9 each and supreme $12 each. He spent exactly twice as much on the pepperoni pizzas as he did the cheeese. If Ben spent a total of $168 on pizzas, how many pizzas of each type did he buy?
Answer provided by our tutors
so 6*x+9y+6z=198
and 12x=9y
=>x=0.75y
now x+y+z=19
=>1.75y+z=19
and 6*0.75y +9y+12z=168
=>13.5y+12z=168
now solvinga bove two eauation we get
=>21y-13.5y=60
=>7.5y=60
=>y=8
so x=6
and z=5