Achemist mixes a 10% hydrogen peroxide solution with a 25% hydrogen peroxide solution to create 30 liters of a 15% hydrogen peroxide solution. how many liters of the 10% solution did the chemist use to make the 15% solution?

20 liters

Step-by-step explanation:

Let x liter of 10% hydrogen peroxide solution is mixed with y liter of 25% hydrogen peroxide solution to create 30 liters of a 15% hydrogen peroxide solution.

Thus, Total quantity of mixture = 30

⇒ x + y = 30 (1)

And, Total quantity of hydrogen in the mixture is the sum of total quantity of hydrogen in x liter and y liter,

⇒ 10 % of x +25 % of y = 15 % of 30

⇒ 10 x + 25 y = 450

⇒ 2 x + 5 y = 90 (2)

Equation (2) - 2× Equation (1),

⇒ 3 y = 30

⇒ y = 10

Substitute this value in equation (1),

We get,

x + 10 = 30

⇒ x = 20,

Hence, the quantity of 10% solution chemist used to make the 15% solution = x liter = 20 liter.

20 liters

Step-by-step explanation:

I did it on Edge

answer: a. 74

step-by-step explanation:

it shows divided evenly, so add the 37+37 = 74

-2

7 - 9 = -2

reversed:

-2 + 9 = 7