Ms. England is planning a party for students who have met their goal of reading seven books during the most recent nine weeks of school. Using a total of $112, she plans to get pizzas that cost $12 each and drinks that cost $0.50 each. If she purchases four times as many drinks as pizzas, how many of each should she buy? • Show how you know. • Create equations and use substitution and a table to demonstrate the solution.

Ms. England should buy 8 pizzas and 32 drinks.

Explanation:

Let p = the number of pizzas and d = the number of drinks.  Each pizza costs $12 so the cost of all of the pizzas is ($12)*p.  Each drink costs $0.50, so the cost of all of the drinks is ($0.50)*d.  The total cost, then, is:

Total Cost = Cost of Pizzas + Cost of Drinks

$112 = ($12)p + (($0.50)*d

Now you buy 4 times as many drink as pizzas, so:

Number of Drinks = 4 * (Number of Pizzas)

d = 4*p

Now lets' substitute 4p in place of d in the total cost equation and solve for p:

$112 = ($12)p + ($0.50)*d

$112 = ($12)p + ($0.50)*(4p)        [Substituted 4p in place of d]

112 = 12p + 2p

112 = 14p

Solve for p, the number of pizzas.  Once you have p, the number of drinks is d = 4*p.