The average price of a gallon of gas increased by 12% in 2010 and by 10% in 2011. By what percentage did the average price of a gallon of gas increase between January 1st 2010 and January 1st 2012?

16.67% increase

Step-by-step explanation:

finding the percentage price increase

we need to find the difference in percentage price between the 2 years

12%-10% = 2%

2%/12% x 100% = 100%/6 = 16.67%

20% increase between January 1st 2010 and January 1st 2011