Question

Deniz had a full gallon of milk. She poured out 4 cups of milk. There are 16 cups in 1 gallon. About what percent of the original volume is left?

Answer 1

75%

Explanation:

Answer 2

75% of the original volume is left.

Explanation:

Deniz had a full gallon of milk, or 16 cups of milk, and then she poured out 4 cups of milk. That is:

• 
  `\\ A_(full-gallon) = (16)/(16)` cups of milk, since
  `\\ (16)/(16) = 1` or
  `\\ 1 * 100\% = 100\%` of the original volume.
• Deniz poured out 4 cups of milk from the 16 available (or
  `\\ (4)/(16)`).

Then,

The total left is:

`\\ Total_(left) = (16)/(16) - (4)/(16) = (12)/(16) = (3)/(4)`, since we are dealing here with fractions with the same denominator.

In other words,
`\\ (3)/(4) = 0.75` is the amount of milk left in the container.

In terms of percentage,
`\\ (3)/(4) = 0.75` is equivalent to
`\\ 0.75*100\% = 75\%` of the original volume, because Deniz poured out
`\\ (4)/(16) = (1)/(4) = 0.25` or
`\\ 0.25*100\% = 25\%` from the original volume.

So, Deniz left 75% of the original volume of milk after pouring out 25% of it.

This can be represented in the graph below.