Calculate the number of calories in 1/4 lbs of margarine

There are 700 Cal in ¼ lb margarine.

Dietitians say there are anywhere from 150 Cal to 200 Cal in an ounce of margarine.  

Let’s split the difference and assume 175 Cal/oz.

a. Given: pounds of margarine

b. Want: number of calories

c. Equalities: 175 Cal = 1 oz; 16 oz = 1 lb

d. Conversion factors: 175 Cal/1 oz or 1 oz/175 Cal; 16 oz = 1 lb or 1 lb/16 oz

We choose the conversion factor that has the desired units on top.

Calculation:

No. of ounces = 0.25 lb × (16 oz/1 lb) = 4 oz

No. of Calories = 4 oz × (175 Cal/1 oz) = 700 Cal