Word Problem on Solving for Unknown Value of a Variable

Topic : Solve for unknown value of a variable.

Question: How much solution of 18% Sulphuric acid should be added to 360 ml of 10% solution to make a 15% solution?

Solution :

Let the ml of solution added be ---> x
That is 18% of Sulphuric acid in x
So now we have total
360 + x ml of Solution
So we have
18% of x + 10% of 360 = 15% of (360 + x)
0.18x + 36 = 0.15(360 + x)
Now solve for x,
0.18x +36 = 54 + 0.15x
0.03x = 18
x = 18
     -----   =   600
     0.03

Therefore 600 ml should be added.

Hope the Answer and Explanation will be helpful for you.