Hello, I would love to help!
Alright. First, let's figure out what the problem means.
We need to find 25% of 40, then subtract that number from 40 to find your answer, because the class increased by 25%.
Okay, let's find 25% of 40.
To do that, we need to multitasking the decimal form of 25% (0.25) by 40.
0.25*40=10
Okay, so now we know the class increased by 10 kids. Let's subtract those kids from the new class to find the original class number.
40-10=30
So, the original class size was 30 students.
Answer= 30 students
Hope this helped, comment if you have any questions! :)