Question

. At McDonalds, a packet of ranch dressing has 10 more calories than eight side salads. Three side salad
s and two packets of ranch dressing have a total of 400 calories. How many calories are in each item?

Answer 1

x = 8y+10                 ec. 1
2x + 3y = 400           ec.  2


replacing x from ec. 1 to ec. 2:
2*(8y+10) + 3y = 400
16y + 20 +3y = 400
19y + 20 = 400
19y = 400-20
19y = 380
y = 380/19
y = 20

20 calories in each side salad.

Now on ec. 1:
x = 8y+10
x = 8*20 +10
x = 160 + 10
x = 170

170 calories in each ranch dressing.

Check it out ion ec. 2:

2x + 3y = 400
2*170 + 3*20 = 400
340 + 60 = 400

400 ≡ 400

Regards....