Rectangular marbles are taken to make a floor. The length and breadth of a marble are 4 feet and 3

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19 Mar 2010 Rectangular and Circular block

Rectangular marbles are taken to make a floor. The length and breadth of a marble are 4 feet and 3 feet respectively.
A circular block of radius 1 feet is thrown on the floor at random. The chance that it falls entirely on one rectangular
block is

OPtion

1) 7/12
2) 1/12
3) 3/4
4) 1/2
5) 2/3
6) 5/6
7) 1/6
8) 3.14/7
9) 1.57/6
10) 1.57/3

Solution

The centre of the circular block can be moved in a rectangular area of length and breadth 2 and 1 feet respectively.
Hence chance that it falls entirely on one rectangular block is 2*1/4*3 = 2/12
= 1/6

Correct Option: 7 Best Solution (15)

kewal   14 years AGO

chance that block falls entirely on one rectangular
block = Preferred area / total area = (2*1)/(4*3) = 2/12= 1/6

Like? Yes (1) | No   

Dolly   14 years AGO

2*1/(3*4) = 2/12=1/6

Like? Yes (1) | No   

Dimple   14 years AGO

(2*1)/(4*3) = 2/12= 1/6

Like? Yes (1) | No   

Pargat Pal Singh   14 years AGO

2x1/(4x3) = 2/12= 1/6

Like? Yes (1) | No   

Shikha   14 years AGO

Target area for centre of circular block will be rectangular area of 2x1 ft inside main rectangular block of 4x3 ft.

so chance = 2/12= 1/6

Like? Yes (1) | No   

Garima   14 years AGO

2/12= 1/6

Like? Yes (1) | No   

Ashu   14 years AGO

2/12= 1/6

Like? Yes (1) | No   

Dimple   14 years AGO

2/12= 1/6

Like? Yes (1) | No   

Dr.Dipin Singh   14 years AGO

For circular block of rad 1 ft to lie in one rectangular block, the centre of circular block should lie one ft away from each side/corner of rectangular block of 4 ft x3 ft.
Consider an internal rectangle obtained by leaving 1 ft from each side, we get a rectanglular area of 2 ft x 1 ft.

so chance of circular block falling on one rectangular block = area of internal triangle/ area of rectangular block = 2*1/4*3 = 2/12 = 1/6

Earlier I entered the wrong choice by Mistake.

Like? Yes (1) | No   

Bawa   14 years AGO

2*1/(3*4) = 2/12= 1/6

Like? Yes (1) | No   

Mihir   14 years AGO

2/12= 1/6

Like? Yes (1) | No   

Bimal   14 years AGO

2/12=1/6

Like? Yes (1) | No   

Vasu   14 years AGO

useful area/total area= 2/12= 1/6

Like? Yes (1) | No   

Jagat   14 years AGO

2/12= 1/6

Like? Yes (1) | No   

Dr. Divya   14 years AGO

Preferred area / total area = 2/12= 1/6

Like? Yes (1) | No