Infosys
Company
Numerical Ability
Time Distance and Speed
a train m eaves meerut at 5 a.m and reaches delhi at 9 am. another train delhi at 7 am and reaches meerut at 10.30 am at what time do the two trains cross each other
Read Solution (Total 8)
-
- suppose trains met t hrs after 7 am. and x is distance between Delhi and meerut.
Then
(x/3.5)*t + (x/4)*(t+2)=x
or
t/3.5 + (t+2)/4 =1
Then
t= 7/7.5 hrs or 56 mins.
so trains will meet at 7.56 AM.
- 14 years agoHelpfull: Yes(35) No(6)
- crossing time ...7.56 AM.
Ratio of speeds = 4/3.5 =8/7 - 14 years agoHelpfull: Yes(7) No(8)
- let t be the time, D be the distance.
train m leaves meerut at 5.a.m.
train n leaves delhi at 7.a.m.
so,the two trains are differed by 2 hours.
and let the first train travell for 4hours(from 5.a.m to 9.a.m),so the speed of the first train is:D/4kmph.
and second train travell for 2.30hrs(from 7-10.30a.m)hence speed of second train is:D/2.30kmph=2D/5kmph.
now the two trains meet after 7 am by
t*(D/4)+(t-2)*(2D/5)=D
by solving we get t=12hours.
thus two trains are meet exactly 12 hours after 7.a.m
i.e.at 7p.m - 14 years agoHelpfull: Yes(2) No(24)
- let distance between station =x
so speed of first train v1=x/4
and speed of second train v2=x/3.5
now let both train meet at time T then
distance travelled by first equal to distance leftto travel for second train
5:00 _____________________________(T)fisrt->_____________9:00
10:30______________________________ - 14 years agoHelpfull: Yes(2) No(12)
- let distance between station =x
so speed of first train v1=x/4
and speed of second train v2=x/3.5
now let both train meet at time T then
distance travelled by first equal to distance leftto travel for second train
5:00am _____________________________(T)fisrt->_____________9:00am
10:30am_____________________________ - 14 years agoHelpfull: Yes(1) No(8)
- let distance between station =x
so speed of first train v1=x/4
and speed of second train v2=x/3.5
now let both train meet at time T then
distance travelled by first equal to distance leftto travel for second train
5:00 ____T)fisrt->_____9:00
10:30____ - 14 years agoHelpfull: Yes(1) No(6)
- First train takes 4 hours and the second train takes 3.5 hours.Time ratio is 8:7. Therefore, the speed ratio will be 7:8.Let the speeds be 7x and 8x, and distance be 28x ( 4×7 or 3.5×8).At 7 AM, the first train must have covered a distance of 14x.
Therefore, at 7 A.M. the distance between the two trains is 28x-14x=14x.Time taken to meet = 14x/(7x+8x)=14/15 hour or 56 minutes.Hence, the two trains meet at 7.56 AM. - 6 years agoHelpfull: Yes(1) No(0)
- if the distance between two stations is=x
speed of fist tain= x/4
and of second train=x/3.5
given,n leaves 2 hours after m (7 a.m-5 a.m)
let,in that 2 hours m travers a distance of y
and remaining distance be x
!.........!.........!
< x km >< y km >
when m traversed x km, 2 hours is over
now for y distance in 2 hours the distance between n & m b [{(x/4)+{x/3.5)]
or 7.5x/14 distance reduces in 2 hour between y km
so,x distance traversing needs 56 minutes & including previous time for train m (7am-5am)=2 hours....so total time needed is 2 hours 56 minutes.
so,they will meet on 5a.m+2 hour - 14 years agoHelpfull: Yes(0) No(3)
Infosys Other Question