In a mixture of 90 L the ratio of acid and water is 2 : 1. If the ratio of acid and water is to be 1 : 2, then the amount of water (in liters) to be added to the mixture is?
Answer: C
So amount of acid = 2/ 2+1 × 90 = 60L
Amount of water = 90 - 60 = 30L
To make acid to water ratio = 1:2, we simply need
To make water double of acid.
By direct observation, we can say that we should
have 60L × 2 = 120L make the required ratio
We have 30L, we need (120-30) = 90L more water