101k views
2 votes
A tank has a capacity of 13 gallons. When it is full, it contains 20% alcohol. How many gallons must be replaced with an 70% alcohol solution to give 13 gallons of 30% solution? Round your final answer to 1 decimal place if necessary.

User ShawnD
by
8.0k points

1 Answer

3 votes

Given:

A tank has a capacity of 13 gallons. When it is full.

The tank contains 20% alcohol.

We will find the number of gallons that must be replaced with a 70% alcohol solution to give 13 gallons of 30% solution

Let the number of gallons that must be replaced = x

so, there are x gallons with a 70% alcohol and (13 -x) with a 20% alcohol.

So, we can write the following equation:


70x+20(13-x)=30*13

Solve the equation to find (x):


\begin{gathered} 70x+20*13-20x=30*13 \\ 50x+260=390 \\ 50x=390-260 \\ 50x=130 \\ x=(130)/(50)=2.6\text{ gallons} \end{gathered}

So, the answer will be 2.6 gallons

User Nkemdi Anyiam
by
8.2k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.