The gasoline prices in seven states are $1.96, $2.09, $1.79, $1.61, $1.75, $2.11, and $1.84.

The median gasoline price is. The difference of the first and third quartiles in this set of gas prices is

To find the median is to basically put these values in order from least to greatest and pick the one in the exact middle. Of course, there will be no exact middle if there is an even number of values and to find the median when this is so, you have to add the two middle terms and find the mean (average) of those terms. So:

$1.61, $1.75, $1.79, $1.84, $1.96, $2.09, $2.11

The one that is in the exact middle is $1.84 so this is the median.

To find the difference between the first ($1.61) and third ($1.79) quartiles, just subtract $1.61 from $1.79.

$1.79 - $1.61 = $0.18