Infosys Company Numerical Ability Time Distance and Speed

A train ran at a certain speed for one hour and then due to a technical problem, it ran at 3/5th of its original speed and reached the destination 2 hrs late. The driver said, had the problem occurred 50 miles later, we would have gained 40 minutes. What is the distance between the two cities that the train traveled?

Read Solution (Total 1)

In this question, we have to solve for original time and original speed and then we will calculate the total distance.

Let v & t be the speed & time respectively.
Therefore, total distance=vt mile

FIRST CASE:
(1 hour + time taken to travel after problem) = (original time + 2 hours)
=> 1+ (vt-v)/(3v/5) = t+2
=> (5t-5)/3 = t+1
=> 5t-5 = 3t+3
=> 2t = 8
=> t=4 hour

SECOND CASE:
distance travelled in 1 hour = v*1 mile
i.e. total time taken to travel the journey of vt mile = ( (v+50)/v + (vt-(v+50))/3v/5)
according to question if problem would have occurred after 50 mile then driver would have saved 40 min
=> (t+2) - ( (v+50)/v + (vt-(v+50))/3v/5) = 40/60
=> 6 - (18v-100)/3v = 2/3
=> 18v-18v+100 = 2v
=> 2v = 100
=> v=50 mile/hour

distance = vt = 50*4 = 200 miles

Thus, we have time=4 hour and speed=50mile/hour
Hence total distance= 4*50 mile = 200 mile
Ans 200 miles
11 years agoHelpfull: Yes(5) No(0)

Infosys Other Question

Given a rectangular cake with a rectangular piece removed (any Size or orientation), how would you cut the remainder of the Cake into two equal halves with one straight cut of a knife? To make it Tougher, consider a cake with two rectangular pieces removed (any size or Orientation, and both pieces can be of different orientation and size). A managing director interviewed candidates for a Responsible position in his company, finally arriving at three whom he could Not separate. He called them together and said, "in my desk i have some Small sticky discs, some of which are black and some white. Close Your eyes and i will stick one on the forehead of each of you. You Must then go into the next room which has no furniture or mirrors. You will Be able to see the discs on each of the other two candidates but not your Own. Without anyone touching any of the discs and without talking To one another, the first one who can solve the problem and come out of The room and tell me what color of disc he has on his forehead, with a Logical reason, will get the job." the candidates went into the room and almost Immediately one came out and said, "i have a black disc on my forehead." he was given the job. What was his reasoning?