Measurement

Question

A cookie recipe requires 3/4 cup of flour to make 1 1/2 dozen cookies. How much flour is needed to make 1 dozen cookies

Answer 1

We can use the information to form 2 fractions.

 

For simplicity, let's standardize everything. We'll convert all the fractional values into their decimal values, and we'll convert the phrase "1 dozen" to the number 12.

 

So

 

3/4 = 0.75

 

1 dozen = 12

 

1 and a 1/2 dozen = 12 + 6 = 18

 

 

Now let's rephrase the question.

 

For every 0.75 cups of flour, we can make 18 cookies. This is our first fraction.

 

0.75/18

 

We want to know how many cups of flour x will make 12 cookies. This is our second fraction.

 

x/12

 

Now we equate the two fractions to one another and solve for x.

 

0.75/18 = x/12

 

x = (0.75/18)(12)

 

x = (0.0417)(12)

 

   = 0.50

 

So we need 0.5  or a half-cup of flour to make 12 cookies.

Answer 2

Natalie, we can set up a proportion. I'm going to change 1 1/2 to 3/2.

 

3/4 cups/3/2 dz cookies = f cups/1 dz cookies.

 

Cross multiplying, 3/2f = 3/4

 

Dividing both sides by 3/2, f = 1/2

 

So, one dozen cookies requires 1/2 cup of sugar.

 

Hope this helps!