Question

Two vessels A and B contain acid and water in the ratio 4 : 7 and 6 : 5 respectively. Their contents are mixed in the ratio 2 : 3. How much acid should be added to 440 mL of this solution to get a 50% acid solution? 
1. 24 mL
2. 20 mL
3. 18 mL
4. 26 mL

Answer 1

Correct Answer - Option 1 : 24 mL

Given:

Two vessels A and B contain acid and water in the ratio 4 : 7 and 6 : 5 respectively

They are mixed in the ratio of 2 : 3

Calculation:

Let the total quantity of A and B which mixed in ratio 2 : 3 be 22x and 33x respectively

Acid in A and B respectively = 8x + 18x = 26x

Water in A and B respectively = 14x + 15x = 29x

According to the question:

22x + 33x = 440

⇒ x = 8

Total acid = 26 × 8 = 208

Total water = 29 × 8 = 232

∴ Acid needs to added  = 232 - 208 = 24 ml