One way to compute a 20% discount is to multiply it by 0.20. The price of a pair of sneakers is $84.50. Calculate the discount. Explain or show your reasoning.
Answers
Answer:
Note that multiplying by 0.833¯ is really dividing by 1.2. In order to know which one is right, you need to keep in mind which number represents 100%, or the origin. Calculating percentages from the origin is done by multiplying, while recovering the origin from some given percentage is done by dividing.
So finding 80% of a price is done by multiplying with 0.8. If you have the 80% price and want to find the original price, you divide by 0.8 (which becomes multiplying by 1.25).
So multiplying with 0.833¯, when we're talking about 20% and not 16.66¯%, is, as mentioned above, really dividing by 1.2. That means that what we find is the original price when we're given the new price after a 20% price increase. That's not the same as finding 80%.