In January, gasoline cost $1.05 per gallon. In July, gasoline cost $1.20 per gallon. Find the percent of increase.

Question

Would the answer for this question be 14.3?

And how do you do percent of decrease?
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The original cost of a computer is $900. If the price is decreased by 15%, what is the sale price?

I need help with this question(:
Thank you

Answer 1

percent (increase or decrease) is

Percent= (final-initial)/initial * 100

fifteen percent of 900 is 130 dollars.
so the cost is 900-130 dollars

price=(100-percentdecrease)/100 * 900

Answer 2

bob, this looks kind of like exponential growth and exponential decay, is it? I was just wondering since we just started on exponential decay today.