The number of students in class increased from 10 to 15. What is the percent increase?

1 Answer
May 21, 2016

#50/100 -> 50%#


There are 2 ways of writing percent, both of which mean the same thing. They just look different.

Example: Suppose we had sixty percent. This can be written as

#60%" or "60/100 #

The ward part of 'per' in percent means 'for each of'.
The word part of 'cent' in percent means 100. Think of century which is 100 years.
The level of increase is 15-10=5, but this is part of the total original count of ten. So the change as a fraction is :

#(15-10)/10 = 5/10#

To change this to percentage we change the bottom number (denominator) to 100.

#color(brown)("What we do to the top we do to the bottom")#

Multiply by 1 but in the form of #1=10/10#

#5/10xx1" "->" "5/10xx10/10" " =" " 50/100#

#color(green)("So the increase is "50/100 -> 50%)#