Question

A catering company’s recipe for salad uses a ratio of 2 c of dressing to 4 lb of vegetables. (Hint: c = cups; lb = pounds) (a) How many cups of dressing will be needed if 30 pounds of vegetables are used? (b) Draw a model for the ratio. The butterfly method works well for this.

Answer 1

A. 15 cups

B. Diagram below

We are given that,

The ratio of dressing to the vegetables is 2 cups : 4 pounds.

A. It is given that the vegetables are of 30 pounds.

Let the number of cups be x.

Since, the ratio of dressings and vegetables will remain same.

We have,

`(2)/(4)=(x)/(30)`

i.e.
`x=(2* 30)/(4)`

i.e. x= 15

Thus, we will need 15 cups of dressings for 30 pounds of vegetables.

B. As we have obtained the fractions,

2 cups : 4 pounds and 15 cups : 30 pounds

Using the butterfly method, we see from the diagram that these fractions are equivalent because the product of the numbers is equal to 60.