Question

together, a double cheeseburger and a small order of fries cotains 690 calories. the fries have half as many calories as the double cheeseburger. determine the number of calories in each

Answer 1

x+y=690
y=x/2

x= calories in double cheeseburger
y= calories in fries

set both problems to y then set them equal to each other like so...
y=690-x
y=x/2

690-x=x/2 times by 2
1380-2x=x Add 2x to other side
1380=3x divid by 3
x=460

To find y plug 460 into y=x/2
y=460/2
y=230


cheeseburgers have 460 calories and fries have 230 calories.