I cannot really explain my side of the calculations more than I already have so I will address
Quote:
However, we are working backward, we are going back, on the contrary so we must add 20%. So, 145.6*1.2= 174.72
I am also working backward. I would like to clarify that the 20% we are adding back is not 20% of 145.6, but 20% of the original unknown price. To rephrase it:
Unknown price X is > 145.6
Decrease X by 20% first: we take 0.2*X, which is equal to 20% of unknown price X, and then subtract it from X to arrive at a new decreased price of 145.6
Here is a comparison to my simpler example for each step
X - 0.2(X) = 80
X - 0.2(X) = 145.6
X(0.8) = 80
X(0.8) = 145.6
X = 80/0.8 = 100
X = 145.6/0.8 = 182
Notice the error is in the 20% you take.
We all agree 80*1.2 =/= 100.
We all agree 80*1.25 = 100.
This means we KNOW we should not multiply by 1.2, but instead by 1.25.
Quote:
if you at the time had a discount of 20% BUT now you are working backward you do not have 20% off (minus) anymore
If we are asked to find the original price, which at some point was modified by 20% off, then I will have to incorporate that 20% off to work backwards and find it. I don't know if we just don't agree on the phrasing used in the question but I will ask some people to double check this for me.
EDIT; I appreciate you taking the time to write out your explanations. I've asked some other people to double check this for what I'm having an issue understanding about the original prompt.