Question

A chemist 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?

Answer 1

20 liters

Explanation:

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Answer 2

Answer: 20 liters

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.