15/40 as a percentage is 37.50%. This number tells you how much of a whole the fraction represents when you look at it on a scale of 100.
The fraction 15/40 can be reduced to 3/8, which is an easy way to see the same value in a simpler form. Whether you write it as 15/40, 3/8, or 37.50%, the amount stays the same.
Knowing the percentage makes it quick to compare this part to other numbers, like grades, discounts, or statistics, because most people think in terms of hundreds. It’s a handy way to communicate the size of the fraction in everyday situations.
