Quantity, percentage, percentage value: Convert fractions to percentages

A percentage is actually a form of a fraction, or more precisely, a fraction out of a hundred.

In other words, a fraction where the denominator is always 100.

Therefore, in order to convert a fraction into a percentage, we multiply it so that the denominator becomes 100.

20*5=100

15*5=75

So the fraction is 75/100, and the percentage is 75%.

To solve the exercise, will begin by converting the percentage into a fraction:

$42\%=\frac{42}{100}$

We will then proceed to multiply the fraction by 15

$15\times\frac{42}{100}=$

In order to simplify this operation let's break down the 15 from the multiplication exercise as well as the 100 in the denominator for the multiplication exercise:

$3\times5\times\frac{42}{5\times20}$

Take note that the five in both exercises can be reduced:

$3\times\frac{42}{20}=\frac{3\times(2\times21)}{2\times10}$

Furthermore we can also reduce the 2 in the numerator and the denominator:

$\frac{3\times21}{10}=\frac{63}{10}=6.3$