Amy K. answered 01/26/21
Professional Chemist with Tutoring Experience
let x = pizza and y = salad
We can write 2 equations from the information given:
6x + 2y = 80 and
3x + 4y = 61
If we multiply the first equation by 2 so we have the same number of y in each equation we get:
2(6x + 2y = 80) or 12x +4y = 160
Then we can subtract the second equation from the first equation (which has been multiplied by 2);
12x +4y = 160
-(3x + 4y = 61)____
9x = 99
Now solving for x we get:
9x = 99_ or x = 11
9 9
We can plug our newly found x back into either equation and solve for y (I'll use the first equation):
6(11) + 2y = 80
66 + 2y = 80
2y = 14
y = 7
Therefore, pizzas cost $11 and salads cost $7.