How many liters each of a [tex]25 \%[/tex] acid solution and a [tex]65 \%[/tex] acid solution must be used to produce 80 liters of a [tex]45 \%[/tex] acid solution? (Round to two decimal places if necessary.)



Answer :

To determine the amount of each solution needed to produce the desired mixture, we need to set up and solve a system of equations based on the information given.

1. Define Variables:
- Let [tex]\( x \)[/tex] be the amount of the 25% acid solution.
- Let [tex]\( y \)[/tex] be the amount of the 65% acid solution.

2. Set Up Equations:
- The total volume of the mixture is 80 liters, so:
[tex]\[ x + y = 80 \][/tex]
- The total amount of acid in the mixture is 45% of 80 liters. The equation for the total acid content is:
[tex]\[ 0.25x + 0.65y = 0.45 \times 80 \][/tex]

3. Solve the System of Equations:
- The first equation is:
[tex]\[ x + y = 80 \][/tex]
- The second equation, converting 0.45 * 80, we get:
[tex]\[ 0.25x + 0.65y = 36 \][/tex]

4. Isolate one variable:
From the first equation, solve for [tex]\( y \)[/tex]:
[tex]\[ y = 80 - x \][/tex]

5. Substitute [tex]\( y \)[/tex] in the second equation:
Substitute [tex]\( y \)[/tex] from the first equation into the second equation:
[tex]\[ 0.25x + 0.65(80 - x) = 36 \][/tex]

6. Simplify and Solve for [tex]\( x \)[/tex]:
[tex]\[ 0.25x + 52 - 0.65x = 36 \][/tex]
[tex]\[ 52 - 36 = 0.4x \][/tex]
[tex]\[ 16 = 0.4x \][/tex]
[tex]\[ x = 40 \][/tex]

7. Find [tex]\( y \)[/tex] using the value of [tex]\( x \)[/tex]:
Substitute [tex]\( x = 40 \)[/tex] back into the equation [tex]\( y = 80 - x \)[/tex]:
[tex]\[ y = 80 - 40 \][/tex]
[tex]\[ y = 40 \][/tex]

So, to produce 80 liters of a 45% acid solution, you need:

- 40 liters of a 25% acid solution
- 40 liters of a 65% acid solution