Question

half a pepperoni pizza plus three fourths of a ham and pineapple pizza contains 765 calories 1/4 of a pepperoni pizza plus a whole ham and pineapple pizza contains 745 calories how many calories are in a whole pepperoni pizza and how many calories are in a whole ham and pineapple pizza

a) 600 calories, 550 calories
b) 480 calories, 640 calories
c) 520 calories, 680 calories
d) 660 calories, 580 calories

Answer 1

Answer:

Correct choice is D (In a whole pepperoni pizza are 660 calories, in  in a whole ham and pineapple pizza are 580 calories).

Step-by-step explanation:

Let x calories be the number of calories a whole pepperoni pizza contains and y calories be the number of calories a whole ham and pineapple pizza contains.

1. If half a pepperoni pizza plus three fourths of a ham and pineapple pizza contains 765 calories, then

$\dfrac{1}{2}x+\dfrac{3}{4}y=765.$

2. If 1/4 of a pepperoni pizza plus a whole ham and pineapple pizza contains 745 calories. then

$\dfrac{1}{4}x+y=745.$

3. Multiply each equation by 4 and get a system of two equations:

$\left\{\begin{array}{l}2x+3y=3060\\x+4y=2980\end{array}\right.$

From the second equation $x=2980-4y$, then

$2(2980-4y)+3y=3060,\\ \\5960-8y+3y=3060,\\ \\-8y+3y=3060-5960,\\ \\-5y=-2900,\\ \\y=580.$

Then

$x=2980-4\cdot 580=2980-2320=660.$