 Hi friends and how are you all? The question says a village having a population of 4,000 require 150 liter of water per head per day. That means 4,000 people will require 150 liter of water per head or per day. It has a tank measuring 20 meters into 15 meters into 6 meters. For how many days will the water of this tank last? Let us first find out the capacity of this tank. Here the length, breadth and height of this tank is given to us as 20 meters, 15 meters and 6 meters respectively. Since this is a cuboidal tank we can find out the volume of this tank by multiplying length with breadth with height that is 20 into 15 into 6 that is equal to 1800 meter cube. Now we know that water required per day by 4,000 people will be equal to everybody required 150 liter of water. It will get multiplied by the number of persons in that village and the answer will come out to be lakh liter. It will be converted into meter since we have the volume in meter cube. So that will be 6 lakh divided by 5,000 get converted into meter cube that is 600 meter cube. Now number of days the water will last is everyday 600 meter cube of water is required and in the tank we have 1800 meter cube. So on simplifying we get the answer as 3 days. Right, so this becomes the answer to the question. Hope you enjoy and have a good day.