Two solutions of acid and water containing acid and water in the ratio 2 : 7 and 4 : 5, respectively are mixed in the ratio 2 : 5. What is the ratio of acid and water in the resulting solution?
Show answer & explanation
Correct answer: A
Explanation
The correct answer is option 1 i.e. 8 : 13.
The amount of acid in 1st solution = 2/9
The amount of acid in 2nd solution = 4/9
They are mixed in the ratio 2 : 5.
Let x be the acid present in the final mixture.
Using the principle of allegations -
((4/9) - x)/(x - (2/9)) = 2/5
(20/9) - 5x = 2x - (4/9)
7x = 24/9
x = 8/21
8 parts of acid and 13 parts of water.
Required ratio = 8 : 13