Question

A chemist has one solution containing 50% acid and a second one containing 25% acid. How much of each should be used to make 10 litres of a 40% acid solution?

Answer 1

Let x litres and y litres be the amount of acids from 50% and 25% acid solutions, respectively.

As per the question

50% of x + 25% of y = 40% of 10

⇒ 0.50x + 0.25y = 4

⇒ 2x + y = 16   ...(i)

Since, the total volume is 10 liters, so

x + y = 10

Subtracting (ii) from (i), we get

x = 6

Now, putting x = 6 in (ii), we have

6 + y = 10

⇒ y = 4

Hence, volume of 50% acid solution = 6 litres and volume of 25% acid solution = 4 litres.