Question

A box of cereal states that there are 90 calories in a 3/4 cup serving.What is the unit rate for calories per? cup? How many calories are there in 4 cups of the? cereal

Answer 1

480

Explanation:

Let x be the calories in 4 cups

Set it up

`(90)/((3)/(4))=(x)/(4)`

Step 1: Switch sides

`(x)/(4)=(90)/((3)/(4))`

Step 2: Apply fraction rule

`(x)/(4)=(90\cdot \:4)/(3)`

Multiply

`(x)/(4)=(360)/(3)`

Divide

`(x)/(4)=120`

Step 3: Multiply both sides by 4

`(4x)/(4)=120\cdot \:4\\\\=480`

There are 480 calories in 4 cups of the cereal.

Answer 2

Answer: unit rate for calories per cup = 120

calories in 4 cups of cereal = 480

Solution:

Total number of calories in a box of cereal = x calories

Calories in 3/4 cup serving = 90

How many calories in 4 cups = c

How many calories per cup = x

Unitary method

Cups Calories

3/4 90

1 x

Corss multiply

3/4 * x = 90 * 1

x = 90 * 4/3

x = 120 calories

Now for 4 cups,

Cups calories

1 120

4 c

(Cross multiply)

1 * c = 120 * 4

c = 480 calories answer