Question

If 2 pieces of pizza and 3 candy bars cost $8 and 6 pieces of pizza and 5 candy bars cost $20, what is the cost of one piece of pizza? What is the cost of one candy bar?

Answer 1

One piece of pizza = $2.5

One candy bar = $1

Explanation:

Call 1 pizza a, 1 candy bar b. We have:

2a + 3b = $8

=> 3(2a+3b) = 3. $8

= 6a + 9b = $24

and

6a + 5b = $20

=> (6a + 9b) - (6a + 5b) = 9b - 5b = 4b = $24 - $20 = $4

=> b = $1

=> 2a + $3 = $8

=> 2a = $5

=> a = $2.5

So one piece of pizza = $2.5, one candy bar = $1