How many liters each of a 50% acid solution in a 60% acid solution must be used to produce 80 L of a 55% acid solution

Question

I do not know how to answer this question please help

Answer 1

Old Question, but I find this question interesting and seems like it might be useful for future reference.

So, I am posting the solution. If it is inappropriate then it can be deleted. Thank You.

Solution:

Let x be the amount of 50% acidic solution in litres and y be the amount of 60% acidic solution.

Given,

x + y = 80   ------------------------ (1)

and 50x + 60y = 55 * 80  --------------------------- (2)

multiplying eq 1 with 50 and subtracting from eq (2), we get:

10y = 400

=> y = 10

and x = 80 - y = 40

So 40 litres of both solution should be added to produce 80L of 55% solution