Gasoline is a mixture composed primarily of hydrocarbons such as isooctane, which is also known as 2,2,4-trimethylpentane.
gasoline is assigned a number called an octane rating. gasoline with an octane rating of 87 performs the same as a mixture that consists of 87% isooctane and 13% heptane.
an alternative fuel, e-85, can be used in some automobiles. this fuel is a mixture of 85% ethanol and 15% gasoline.

state the octane rating of a gasoline sample that performs the same as a mixture consisting of 92% isooctane and 8% heptane.
identify the functional group in a molecule of ethanol in the alternative fuel e-85.