Q. A vessel full of water weighs 40 kg. If it is one-third filled, its weight becomes 20 kg. What is the weight of the empty vessel?
(a) 10 kg
(b) 15 kg
(c) 20 kg
(d) 25 kg
Correct Answer: (a) 10 kg
Question from UPSC Prelims 2020 CSAT Paper
Explanation :
A vessel full of water weighs 40 kg
GIVEN:
– Full vessel weighs 40 kg
– One-third filled vessel weighs 20 kg
SOLUTION:
1. Weight difference = 40 – 20 = 20 kg
This is weight of 2/3 water
2. Weight of 1/3 water = 20/2 = 10 kg
3. Empty vessel weight = Weight of 1/3 filled – Weight of 1/3 water
= 20 – 10 = 10 kg
ANSWER: The empty vessel weighs 10 kg
