Question

How many liters each of a 25% acid solution and a 65% acid solution must be used to produce 80 liters of a 40% acid solution? (round to two decimal places if necessary.)

Answer 1

50

Explanation:

To solve this problem, we can use the following formula:

(amount of solution 1) + (amount of solution 2) = total amount of mixture

We can also set up equations for the amount of acid in each of the solutions:

0.25(amount of solution 1) + 0.65(amount of solution 2) = 0.4(total amount of mixture)

We have two equations and two unknowns, so we can solve for the amounts of each solution. Let's set x to be the amount of the 25% acid solution and y to be the amount of the 65% acid solution. Then we have:

x + y = 80 (equation 1)

0.25x + 0.65y = 0.4(80) (equation 2)

We can simplify equation 2 by multiplying everything by 100, to get rid of the decimals:

25x + 65y = 3200

Now we can solve this system of equations. One way to do this is to solve equation 1 for one of the variables, and substitute it into equation 2. We get:

x = 80 - y

25(80 - y) + 65y = 3200

2000 - 25y + 65y = 3200

40y = 1200

y = 30

So we need 30 liters of the 65% acid solution. To find the amount of the 25% acid solution, we can substitute y = 30 into equation 1:

x + 30 = 80

x = 50

So we need 50 liters of the 25% acid solution. Therefore, we need 50 liters of the 25% acid solution and 30 liters of the 65% acid solution to produce 80 liters of a 40% acid solution.