Answer:
$ 33.6 to fill this tank, provided a community cost of $2.8 per gallon
Explanation:
1. Let us first find the volume of the gas the tank, by the general multiplication of Base * height ⇒ 11 inches * 1.25 feet * 1.75 feet. For the simplicity, we should convert feet ⇒ inches, as such: 1.25 feet = 1.25 * 12 inches = 15 inches, 1.75 feet = 1.75 * 12 inches = 21 inches. Now we have a common unit, let us find the volume ⇒ 11 in. * 15 in. * 21 in. = 3465 inches^3.
2. Let us say that the the average price of gas in my community is $2.8 per gallon. We would first have to convert inches ⇒ gallons provided 1 gallon = 231 inches: 3465/231 = 15 gallons.
4. Now simply multiply this price of 2.8 dollars per gallon by the number of gallons to receive the cost if the tank was full: 2.8 * 15 = $ 42 if this tank was full provided a community cost of $ 2.8 per gallon
5. Now this tank is 20% full, so we must calculate the cost to fill the other 80% up. That would be 80/100 * 42 = 4/5 * 42 = 168/5 = $ 33.6 to fill this tank, provided a community cost of $2.8 per gallon