The owner of a 5000-gal oil truck loads the truck with gasoline and kerosene. The profit on each gallon of gasoline is 16¢ and on each gallon of kerosene it is 15¢. How many gallons of each fuel did the owner load if the profit was $780?

3000 gallons of gasoline and 2000 gallons of kerosene

Step-by-step explanation:

The first thing is that 16 ¢ and 15 ¢ are 16 and 15 cents, therefore we can express it as $ 0.16 and $ 0.15 respectively.

Now, we can solve by means of a 2x2 system of equations, we have to:

"x" is the number of gallons of gasoline

"y" be the number of gallons of kerosene

x + y = 5000 => x = 5000 - y

0.16 * x + 0.15 * y = 780

replacing

0.16 * (5000 - y) + 0.15 * y = 780

800 - 0.16 * y + 0.15 * y = 780

-0.01 * y = 780 - 800

y = -20 / -0.01

y = 2000

Therefore x:

x = 5000 - 2000

x = 3000

which means 3000 gallons of gasoline and 2000 gallons of kerosene