Exams

Since, in one hour, two hands of a clock coincide only once, so, there will be value.
Required time T = 211H×30 + Ao minutes past H.
Here H - initial position of hour hand = 2 (since 2 O'clock)
A° = Required angle = 0° (Since it coincides)

T = 2112×30 + 0o minutes past 2 

=> 11011 minutes past 2

Let length = x meters, then breadth = 0.6x 

Given that  perimeter = 800 meters 

=> 2[ x + 0.6x] = 800 

=> x = 250 m 

Length = 250m and breadth = 0.6 x  250 = 150m 

Area = 250 x 150 = 37500 sq.m

distance covered in 1 revolution = 2πr = 2 x (22/7) x 20 = 880/7 cm
required no of revolutions = 17600 x (7/880) = 140

A magnetic disk is a storage device that uses a magnetization process to write, rewrite and access data. It is covered with a magnetic coating and stores data in the form of tracks, spots, and sectors. Hard disks, zip disks, and floppy disks are common examples of magnetic disks.

Hence, Magnetic disks are the most popular medium for both Direct access and Sequential access.

Let 'B' alone can do the work in 'x' days

6/30 + 18/x = 1

=> x = 22.5

1/30 + 1/22.5 = 7/90 

=> 90/7 = 12 6/7 days