Question

Dennis want to fill 55-gallon drums with a 20% winter mixture of antifreeze for customers. Dennis wants to mix 100% antifreeze with a 10% antifreeze mix to get the 20% mixture. How many gallons of 100% antifreeze and 10% antifreeze does he need in order to fill the drum?

Answer 1

The number of gallons of 100% mixture to be added is 6.11 gallons and the 10% mixture to be added is 48.89 gallons.

Explanation:

Let us assume that x gallons of 10% mixture and y gallons of 100% mixture are added to make 55 gallons of 20% mixture.

So, x + y = 55 ............. (1)

And
`(0.1x + y)/(x + y) = 0.2`

⇒ 0.1x + y = 0.2x + 0.2y

⇒ 0.1x = 0.8y

⇒ x = 8y ........... (2)

So, from equation (1) we get, 8y + y = 55

⇒ 9y = 55

⇒ y = 6.11 gallons.

Therefore, the number of gallons of 100% mixture to be added is 6.11 gallons and a 10% mixture to be added is (55 - 6.11) = 48.89 gallons. (Answer)