a2zinterviews

4.	A boat having a length 3 m and breadth 2 m is floating on a lake. The boat sinks by 1 cm when a man gets on it. The mass of man is
	A.  12 kg
	B.  60 kg
	C.  72 kg
	D.  96 kg

Solution

Volume of water displaced = (3 x 2 x 0.01)m3 = 0.06m3. Mass of man =Volume of water displaced ×Density of water = (0.06×1000) kg = 60 kg.

5.	The heights of a wall is six times its width and the length of the wall is seven times its height. If volume of the wall be 16128 cu .m, its width is
	A.  4 m
	B.  4.5 m
	C.  5 m
	D.  6 m

Solution

Let the width of the wall be x metres. Then, Height = (6x)m and length= (42x)m. 42x × x ×6x = 16128 x3‹=› (16128 / 42 × 6)= 64 ‹=› x= 4.

6.	How many bricks, each measuring 25 cm x 11.25 cm x 6 cm, will be needed to build a wall of 8 m x 6 m x 22.5 cm?
	A.  5600
	B.  6000
	C.  6400
	D.  7200

Solution

Number of bricks = Volume of the wall/Volume of 1 brick =(800x600x22.5 /25x11.25x6) = 6400.