If 18 is 50% of what number, what is that number?

To determine the unknown number when given that 18 is 50% of it, you can set up a simple equation. The phrase "50% of what number" can be interpreted mathematically as (0.5 \times x), where (x) is the unknown number.

The equation can be formulated as:

[ 18 = 0.5 \times x ]

To solve for (x), you would isolate it by dividing both sides of the equation by 0.5:

[ x = \frac{18}{0.5} ]

Calculating this gives:

[ x = 36 ]

Thus, the correct number is 36, which means that when you take 50% of 36, you will indeed obtain 18. This shows the relationship between the parts and the whole, confirming that 36 is the correct answer.