Q24 of 35 Page 74

Let us write true/false of the following statements:

(i) If the length of each of a cube is twice of that 1st cube then the


volume of this cube is 4 times more than that of the 1st cube.


(ii) In rainy season, the height of rainfall in 2 hectare land is 5 cm, the volume of rain water is 1000 cubic metre.


[hint: 1 are = 100 sq. m,1 hectre = 100are]

(i) FALSE


Let the side of 1st cube be a cm.


volume of 1st cube = a3


Now, as length of 2nd cube = 2a


Then , volume becomes = (2a)3 = 8a3 = a3 + 7a3


i.e. its 7 times more than that of 1st cube.


(ii) FALSE


Area = 2 hectares = 2 × 100 acres = 200 × 100 sq m = 20000 sq m


height = 5 cm = 0.005 m


Thus,


volume of rain water it can hold = area×height


= 20000 × 0.005 = 100 m3


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