Question

30% of the students in a class score an A on the last test. There are 50 students in the class. How many students scores an A on the test?​

Answer 1

15

Explanation:

Percentages represent a proportion of a number. There are 2 ways to find a percent of a whole number.

Multiple of 10

Since 30% is a multiple of 10%, there is a shortcut we can use. We can find 10% and then multiply by 3 in order to find 30%. First, find 10% of 50. Like always, 10% of any number is that number divided by 10 (move the decimal 1 place to the left).

• 50/5 = 10

So, 10% of 50 is 5.0.

Then, to find 30%, multiply 5 by 3.

• 5*3 = 15

30% of 50 is 15.

Multiplication

The more consistent method includes multiplication, this can be used with any percentage. To use this method we need to convert 30% to a decimal. To convert any percentage to a decimal divide by 100 (move the decimal 2 places to the left).

• 30% / 100 = 0.30

Now, we can multiply this decimal by the whole number, 50. This will give us our desired answer.

• 0.30*50 = 15

So, this once again shows that 30% of 50 is 15.