a2zinterviews

20.	A toothed wheel of diameter 50 cm is attached to a smaller wheel of diameter 30 cm. How many revolutions will the smaller wheel make when the larger one makes 15 revolutions?
	A.  18
	B.  20
	C.  22
	D.  25

Solution

Distance covered by smaller wheel in 1 revolution = (2Π x 15) cm = (30 Π) cm. Distance covered by larger wheel in 1 revolution = (2Π x 25) cm = (50 Π) cm. Let k x 30 Π = 15 x 50 Π. Then, k = [15 x 50 Π / 30 Π] = 25. ∴ Required number of revolutions = 25.

21.	What is the least number of square tiles required to pave the floor of a room 15 m 17 cm long and 9m 2 cm broad?
	A.  724
	B.  804
	C.  814
	D.  844

Solution

Length of largest tile = H.C.F. of 1517cm & 902cm = 41cm. Area of each tile = (41 x 41)cm2 ∴ Required number of tiles = [1517x902/41x41] = 814.

22.	A square and a rectangle have equal areas. If their perimeters are p1 and p2 respectively, then
	A.  p1 < p2
	B.  p1 = p2
	C.  p1 > p2
	D.  none of these

Solution

A square and a rectangle with equal areas will satisfy the relation p1 < p2.

23.	If the circumference and the area of a circle are numerically equal, then the diameter is equal to
	A.  Π/2
	B.  2Π
	C.  2
	D.  4

Solution

2ΠR = ΠR2 R = 2 ∴ 2R = 4. Hence, diameter = 4.