Question

The people of the land of unsymmetrix to ensure that there is very little symmetry in life. Even their unit of length (no one knows what it is) is called as unsym. It is their pride that the front wheel and the real wheels of their bikes are of different sizes but are made so that they will not slip on the road . In a certain model of bike the radius of the front wheel is 28 unsyms and that of the back wheels is 14 unsyms after driving a certain distance if front wheel had revolution 54 times how many revolution would the back wheel have undergone?

a. 136

b. 122

c. 108

d. 94

Answer 1

Hi ,

i ) Front wheel radius ( R ) = 28

Revolutions ( N ) = 54

ii ) Back wheel radius ( r ) = 14

revolutions = n

nr = NR

n = ( NR )/r

n = ( 54 × 28 )/14

n = 54 × 2

n = 108

Option ( c ) is correct.

I hope this helps you.

: )

Answer 2

Find the circumference of the front wheel:

Circumference = 2πr

Circumference = 2π(28) = 56π unsyms

Find the total distance covered by the front wheel:

1 revolution =  56π unsyms

54 revolutions = 56π x 54 = 3024π unsyms

Find the circumference of the back wheel:

Circumference = 2πr

Circumference = 2π(14) = 28π unsyms

Find the number of revolutions made by the back wheel:

Number of revolutions = 3024π ÷ 28π  = 108

Answer: (C) 108 revolutions