Question

A recipe for pie dough calls for a ratio of butter to flour of 2/3: 1 3/4. If you plan to use 7 cups of flour, how much butter should you use to keep the same ratio?

A. 2 1/3 cups
B. 2 2/3 cups
C. 3 cups
D. 3 1/3 cups

Answer 1

To find the amount of butter for the given ratio, set up a proportion using the ratio of butter to flour. Solve the proportion by multiplying both sides by the reciprocal of the denominator of the second fraction. The amount of butter you should use is 4 cups.

Step-by-step explanation:

To find the amount of butter you should use, you need to set up a proportion. The ratio of butter to flour is 2/3 : 1 3/4. Since the recipe calls for 7 cups of flour, let x represent the amount of butter. The proportion can be set up as (2/3)/(1 3/4) = x / 7 cups.

First, convert the mixed number 1 3/4 to an improper fraction. Multiply the whole number (1) by the denominator (4) and add the numerator (3), then put that result over the denominator: (4 * 1 + 3) / 4 = 7/4.

Now, solve the proportion: (2/3) / (7/4) = x / 7 cups. To simplify, multiply both sides of the equation by the reciprocal of 7/4, which is 4/7. Multiply the left side to get (2/3) * (4/7) = 8/21, and multiply the right side to get x = (7 cups) * (4/7) = 4 cups.

Therefore, you should use 4 cups of butter to keep the same ratio.