Question

A​ low-calorie bread has 120 calories in a 3​-slice serving. This is 10​% fewer than the number of calories in a serving of regular bread. How many calories are in the same size serving of regular​ bread?

Answer 1

This is a matter of ratios

Explanation:

120 kcal is equivalent to 90% of normal bread (=10% less)

So `120kcaldiv90%=Xdiv100%`

Or: `120/90=X/100`

Cross-multiply: `90xxX=120xx100`

`->X=(120xx100)/90~~133kcal`