Home > Algebra > Percent of Change

Tonya said the percent increase from 25 to 40 is 37.5%. Describe Tonya's error and give the correct percent increase?

Answer 1

Ethan Adkins

The absolute increase is #40-25=15#

The error is that this was taken as a percentage of the new situation: #15/40xx100%=37.5%#

But increase (or decrease) is always taken from the old situation: #15/25xx100%=60%#

The rule is: Increase/decrease% #=("New"-"Old")/("Old")xx100%#

Where a negative outcome means a decrease.

By signing up, you agree to our Terms of Service and Privacy Policy

Answer 2

Ethan Adkins

Tonya's error is calculating the percent increase incorrectly. The correct percent increase from 25 to 40 is 60%.

By signing up, you agree to our Terms of Service and Privacy Policy

Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.