Q21 of 35 Page 74

The daily requirement of water of 3 families in our 3 storeyed flat are 1200L,1050L and 950L respectively. After fulfilling these requirement in order to put up a tank again and to deposit to store 25% of the required water, only a land having a length of 2.5m and breadth of 1.6m has been poured. Let us calculate the depth of tank in metre that should be made.

If the breadth of the land would be more by 4 dcm, then let us calculate the depth of the tank to be made.

Given, Length of tank = 2.5m

breadth of tank = 1.6m


Let height of tank be H m


Requirement of 1st family = 1200L = = 1.2 m3


Requirement of 2nd family = 1050L = = 1.05 m3


Requirement of 3rd family = 950L = = 0.95m3


As, 1m3 = 1000 L


According to question,


25% of the requirement is to be stored in a tank.


25% of Requirement of 1st family = = 0.3 m3


25% of Requirement of 2nd family = = 0.2625m3


25% of Requirement of 3rdfamily = = 0.2375m3


As, 25% of the total requirement of the water = volume of the land to be irrigated


0.3 + 0.2625 + 0.2375 = 2.5×1.6×H


0.8 = 4H


H = 0.2m


2nd part: breadth is increased by 4 dcm = 0.4 m


As, length = 2.5 m


Let the new depth be d m


again, As, 25% of the total requirement of the water = volume of the land to be irrigated


0.8 = 0.4×2.5×d


d


d = 0.8 m


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