The contents in beakers A and B are 90 litres of milk and 90 litres of water respectively. Now, 30 litres of milk is taken from A and put into beaker B. After thoroughly mixing, 12 litres of the mixture is taken from B and put into beaker A. Find the percentage of water in beaker A.
A) 14.5%
B) 12.5%
c) 15.5%
D) 17.5%
E) 14.0%
Answer
This is a question on Ratio and Proportion. The best way to solve these questions is to move step by step and analyse the mixture in terms of ratio at every step.
Step 1: When 30 litres of milk is transferred from Beaker A to B
Amount of milk in Beaker A: 60 litres
Amount of water in Beaker A: 0
Amount of milk in Beaker B: 30 litres
Amount of water in Beaker B: 90 litres
Ratio of milk to water in Beaker B is 1 : 3
Step 2: When 12 litres of mixture is transferred from Beaker B to Beaker A, the mixture contains milk to water in the ratio of 1 : 3, i.e. 3 litres and 9 litres respectively
Amount of milk in Beaker A: 63 litres
Amount of water in Beaker A: 9 litres
Amount of milk in Beaker B: 27 litres
Amount of water in Beaker B: 81 litres
Percentage of water in Beaker A = (Amount of water / Total amount of mixture (water + milk))*100 => (9 / 72)*100 = 12.5%
Correct Answer: B
About the Author
GyanOne is an educational services firm focused on premium GMAT coaching, application advisory (with a focus on ISB applications), and interview preparation for B-school admissions. GyanOne operates in the New Delhi region of India and has top global B-school alumni with a minimum score of 770 on the GMAT, as instructors. All GyanOne counsellors are professionally trained top B-school alumni with an experience of 100+ MBA applications behind them.