The gas tank is 20% full. at $3.00 per gallon of gas, find the cost to fill the tank. (1 gal = 231 in.3)

The correct question in the attached figure

we know that

to fill the tank is required--------> 100%-20%--------> 80%
if 20% of the gas tank is-----------------> 288.75 gal
80% --------------------------------------> X gal
X=80*288.75/20--------> X=1155 gal

if 1 gal----------------> cost $3
 1155 gal----------> $X
X=1155*3--------> X=$3465

the answer is
the cost to fill the tank is $3465