a2zinterviews

25.	A rectangular box measures internally 1.6 m long, I m broad and 60 cm deep.The number of cubical blocks each of edge 20 cm that can be packed inside the box is
	A.  30
	B.  53
	C.  60
	D.  120

Solution

Number of blocks = (160×100×60 / 20×20×20) = 120.

26.	A hollow iron pipe is 21 cm long and its external diameter is 8 cm. If the thickness of the pipe is 1 cm and iron weighs 8 g/cm3, then the weight of the pipe is:
	A.  3.6 kg
	B.  3.696 kg
	C.  36 kg
	D.  36.9 kg

Solution

External radius = 4 cm, Internal radius = 3 cm. Volume of iron =(22/7×(42)-(32)×21)cm3 = (22/7×7 ×1×21)cm3 = 462 cm3. Weight of iron = (462 x 8) gm = 3696 gm = 3.696 kg.

27.	A metallic sheet is of rectangular shape with dimensions 48 m x 36 m. From each of its corners, a square is cut off so as to make an open box. If the length of the square is 8 m, the volume of the box (in m3) is
	A.  3220
	B.  4830
	C.  5120
	D.  6420

Solution

Clearly,l = (48 - 16)m = 32 m ‹=›b = (36 -16)m = 20 m, ‹=›h = 8 m.. Volume of the box =(32x20x8) m3 = 5120 m3.