Explanation:

Correct option is 2: 29/41

Let the initial quantity of both mixtures be:
LCM of [(2+3), (3+4)] = 35 litres
So, the amount of acid in the first vessel = (2/5) x 35
⇒ 14 litres
The amount of water in the first vessel = (3/5) x 35
⇒ 21 litres
So, the amount of acid in the second vessel = (3/7) × 35 ⇒ 15 litres
The amount of water in the second vessel = (4/7) × 35
⇒20 litres
When the two mixtures are mixed together,
The resulting quantity of acid 14+ 15 = 29 litres The resulting quantity of water = 21+20=41 litres
Resultant ratio of acid to water = 29/41