You have a container which has the capacity to hold 3 L water. If it already has 2.25 L water in it, how much more water in mL can you still add to fill it completely?

750mL

Explanation:

According to this question, a container which has the capacity to hold 3 L water already has 2.25 L water in it. This means that the container needs (3 - 2.25) = 0.75L to get filled up completely.

However, this question needs the volume of water needed to fill the container in milliliter (mL). To do this, we say;

1L = 1000mL

0.75L = 0.75 × 1000

= 750mL

Therefore, 750mL of water can still be added to fill up the container completely.