90 percent of 20?
Solution for 'What is 90% of 20?'
In the following example consider that:
- The percentage figure is represented by X%
- The whole amount is represented by W
- The portion amount or part is represented by P
The following question is of the type "How much X percent of W", where W is the whole amount and X is the percentage figure or rate".
Let's say that you need to find 90 percent of 20. What are the steps?
Step 1: first determine the value of the whole amount. We assume that the whole amount is 20.
Step 2: determine the percentage, which is 90.
Step 3: Convert the percentage 90% to its decimal form by dividing 90 into 100 to get the decimal number 0.9:
90 = 0.9
Notice that dividing into 100 is the same as moving the decimal point two places to the left.
90.0 → 9.00 → 0.90
Step 4: Finally, find the portion by multiplying the decimal form, found in the previous step, by the whole amount:
0.9 x 20 = 18 (answer).
The steps above are expressed by the formula:
P = W × X%
This formula says that:
"To find the portion or the part from the whole amount, multiply the whole by the percentage, then divide the result by 100".
The symbol % means the percentage expressed in a fraction or multiple of one hundred.
Replacing these values in the formula, we get:
P = 20 × 90 = 20 × 0.9 = 18 (answer)
Therefore, the answer is 18 is 90 percent of 20.