Question

Is there a shortcut when you're trying to find the total on a percent of increase problem? (think finding the total amount due after tax or similar) If so, why does it work?

Answer 1

Answer:

Denote:

Original amount: P

Rate: R (rate might be positive or negative number)

The total amount after considering rate:

TA = P +/- P x R = P(1 +/- R)

This might be the shortcut you are looking for.

Hope this helps!

:)