the price of a comforter just went up by 15%....

Question

The price of a comforter just went up by 15%. The new price, after the increase, is $60. 

a) Explain why you can use the next percent diagram to calculate the price of the comforter before the increase (fill in steps as needed).

   115% -> $60

 

   100% -> ___

Where does the 115% come from, and why is it equated with $60?

b) Explain why you CAN'T calculate the price of the comforter before the increase by decreasing $60 by 15%.

Answer 1

115 comes up because you pay 100% of the original price plus 15% of the original price.

 

$60 = 1.15x  where  x was the original price.

x = 60/1.15