Percetage story problem

Question

Last weeks gas decreased by 2% but increased this week by 7%. The current price this weekend is what percent of last week's price before the changes?

Answer 1

P = price before the changes

 

First, it decreased by 2%, which dropped the price to 0.98P, and then it increased by 7%.  But the 7% increase applies to the decreased price.  So the decreased price increased by 7% to 1.07 times the decreased price.  That makes the current price

 

P' = 1.07 (0.98 P) = 1.0486 P

 

That makes it 104.86% of last week's price.