The ratios of acid and water in vessels A and B are 4: 5 and 7: 5, respectively. In what ratio should the contents of A and B be mixed to get a solution containing 50% acid?
Show answer & explanation
Correct answer: C
Explanation
The correct answer is Option 3 i.e. 3 : 2.
Acid fractions: A's acid = 4/9 and B's acid = 7/12
Let the mixing ratio be (A : B) = x : y
(4/9)x + (7/12)y = 0.5(x + y)
⇒ 16x + 21y = 18x + 18y
⇒ 3y = 2x
⇒ x/y = 3/2