Question

How many ML of a 35% acid mixture and a 95% acid mixture should be mixed to get 120 ML of a 40% acid mixture?

Answer 1

110ML of 35% acid solution must be mixed with 10ML of 95% solution to obtain 120ML of 40% solution.

SOLUTION:

First, set up table. fill in the unknowns with variables x and y. The table is attached below.

From the table shown below, we can easily set up the two equations.

Sum of values of two acids = Value of mixture

0.35x + 0.95y = 48

For convenience, we will multiply the entire equation by 100,

35 x + 95y = 4800 ------ (1)

Now, Sum of amounts of each acid = Amount of mixture

x + y = 120 --------- (2)

Multiply eqn 2 with 35 for easy calculation and derive the equation into one variable.

35 = 35x + 35y = 4200

Subtracting equation (2) from (1), we get

0 + 60y = 600

Thus, 60y = 600

`y = (600)/(60) = 10`

Substituting y = 10 in (2),

35x + 35(10) = 4200

35x + 350 = 4200

35x = 4200 - 350

35x = 3850

`x = (3850)/(35) = 110`

So, we have x = 110 and y = 10

We can conclude that 110ML of 35% acid solution must be mixed with 10ML of 95% solution to obtain 120 ML of 40% solution.