Well....by the use of the word "increase" or "decrease" in the questions themselves, we should be able to answer the first part
Here's 1
Note something important we can write an "x" percent increase as
(1 + the decimal representation of the percent increase )
So......this becomes
84 ( 1 + 12%) = 84 ( 1 + .12) = 84 ( 1.12) = 94.08
Here's 2
Likewise.....we can write an "x" percent decrease as
(1 - the decimal representation of that decrease )
So we have
820 ( 1 - 25% ) = 820 ( 1 - .25) = 820 (.75) = 615
