Answer:
Gasoline price is $2.80 per gallon in August.
The price increased by 15% in September,
dropped 5% in October
and dropped another 10% in November.
The gasoline price in November would be:
2.8 x (1 + 15/100) x (1 - 5/100) x ( 1 - 10/100) = 2.7531
Hope this helps!
:)