Question

A 20% acid solution is mixed with a 70% acid solution to get 50 liters of a 40% solution.

How much of the 70% solution is used?

A.) 20 liters
B.) 25 liters
C.) 30 liters

Answer 1

20% solution+70% solution=50% solution
total is 50
so the quantaties are x and 50-x (x+50-x=50)
0.2(50-x)+0.7(x)=0.4(50)
solve

distribute
10-0.2x+0.7x=20
10+0.5x=20
minus 10 both sides
0.5x=10
times 2
x=20

A is answer

Answer 2

The volume of  70% solution used will be 20 liters. Option A is correct.

What is the percentage?

The quantity of anything is stated as though it were a fraction of a hundred. A fraction of 100 can be used to express the ratio.

Let x is the volume when the 70%  solution is used and the volume of the 2 nd acid solution is x₂

If the total volume of the first acid solution is 50

v₁+v₂= 50

x₁+x₂=50

x₁=50-x₂

A 20% acid solution is mixed with a 70% acid solution to get 50 liters of a 40% solution;

⇒v₁x₁+v₂x₂=vx

⇒0.2(50-x)+0.7(x)=0.4(50)

⇒10-0.2x+0.7x=20

⇒10+0.5x=20

⇒0.5x=10

⇒x=20

The volume of  70% solution used will be 20 liters.

Hence option A is correct.

To learn more about percentages, refer to:

https://brainly.com/question/13450942

#SPJ2