Hi,

A military column of 1 km length marches with a constant speed of 6 kilometers per hour. A courier from the back of the column is sent to the head of the column by bike to deliver a message. Arrived at the front, he
instantly returns. When he returns again at the back, the column has travelled a distance of 1 km since the start of his errand. The courier drove with constant speed.

How fast did the courier bike?


Thanks

Gokulakrishnan K

hi,

i think it is 4km/hour

thanks
Sushma

How Sushma?


Thanks

G K

If i understood the question correctly..

Then the answer is 12Km/hr

thanks
raj

Is 12 Km/Hr right answer??..I am getting 12km/hr

Answer: 12 kmph

Explanation: Column speed = 6 kmph (given)
Distance travelled by Column = 1 km. (given)
Let the time taken by Column to travel 1 km be ' T ' hr.
speed = distance / time ( Basic formulae )
6 = 1/T
T = 1/6 hr ( i.e 0.1666667 hr ) ---> Equation 1

It is given that during this ' T ' hr, courier travelled from back of column to front & from front to back of column. Since the Column is 1 km long, so the distance travelled by courier is 2 km.

Finally applying basic formulae of speed to courier i.e.
speed = distance travelled/ Time taken
= 2 km / 0.166666667 hr ( From equation 1 )
= 2 / 1/6
= 12 kmph --> Q.E.D

kraots & amitpatel66 you guys are right !!..


Cheers,
Anup | Mahindrakar

the speed of courier bike is 0.2777 km/hr