Answer: 40%
Step-by-step explanation: First determine whether the number increases or decreases. Since the number changes from 100 to 140 it's getting bigger, so it increases.
To find the percent increase, we use the following formula.
The amount of change is the difference between the two numbers which is 40 and we get this by subtracting 100 from 140. The original number will be the number that we started with which is 100.
140/100 simplifies to 0.4.
Finally, we want the percent increase so we write 0.4 as a percent by moving the decimal point 2 places to the right to get 40%.
Therefore, the percent increase is 40%.