Given,
The revenue is directly varies to the number of gallon sold.
The revenue of the gas is $51 when the number of gas sold is 15 gallons.
Required
The revenue amount when the number of gas sold is 5.5 gallons.
According to the question,
Here, R = revenue, k is proportionality constant and N = number of gallons sold.
Substituting the values then,
The value of k is 17/5.
The linear equation that relates R to number of gallons of gas is:
The amount of revenue at 5.5 gallons of gas sold.
Hence, the revenue amount is $18.7.