If there are 240 ml of water in the glass now, what was the original volume of water in the glass?

The volume of a glass of water placed in the sun decreases by 20%.

If there are 240 ml of water in the glass now, what was the original volume of water in the glass?
A . 19 2 ml
B . 260 ml
C . 288 ml
D . 300 ml
E . 360 ml

Answer: D

Explanation:

The original volume of water, x, minus 20% of x, 0.20x, is equal to the current volume of water, 240 ml.

x C 0.20x = 240 ml