Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 17)
17.
A train 800 metres long is running at a speed of 78 km/hr. If it crosses a tunnel in 1 minute, then the length of the tunnel (in meters) is:
Answer: Option
Explanation:
| Speed = |  |
78 x | 5 |  |
m/sec | = | |
65 | |
m/sec. |
| 18 | 3 |
Time = 1 minute = 60 seconds.
Let the length of the tunnel be x metres.
| Then, | |
800 + x | |
= | 65 |
| 60 | 3 |
3(800 + x) = 3900
x = 500.
Discussion:
52 comments Page 3 of 6.
Ramya said:
1 decade ago
78 is in kmph but answer is in meter so we should convert km to meter by 5/18 is the formula.
If you want to convert meter into km by 18/5.
If you want to convert meter into km by 18/5.
Saikat said:
4 years ago
=> x+800/60 = 78 * 5/18,
=> x+800/60 = 65/3,
=> x+800 = 65 * 60/3,
=> x+800 = 1300,
=> x = 1300-800,
=> x = 500.
=> x+800/60 = 65/3,
=> x+800 = 65 * 60/3,
=> x+800 = 1300,
=> x = 1300-800,
=> x = 500.
(1)
Anusha said:
1 decade ago
@Kannika
We are adding train length to the tunnel length, because we have to consider the total length so we have to take this.
We are adding train length to the tunnel length, because we have to consider the total length so we have to take this.
Somil kumar bhadula said:
3 years ago
3(800+x) = 1900
2400+3x = 1900
3x = 2400-1900,
3x = 500.
I understand the thing. But where the 3x goes?
Can somebody tell me?
2400+3x = 1900
3x = 2400-1900,
3x = 500.
I understand the thing. But where the 3x goes?
Can somebody tell me?
Narasimha said:
1 decade ago
Hi friends,
If tunnel is x metres
1 mint=60sec
800+x=78*(5/18)60
Solve this and get the ans
Length = Speed*Time
If tunnel is x metres
1 mint=60sec
800+x=78*(5/18)60
Solve this and get the ans
Length = Speed*Time
Naveen said:
6 years ago
X+800 = 78 * 5/18 * 60,
X+800 = 13*5/3 *60,
X+800 = 13*5*20,
X+800 = 65*20,
X+800 = 1300,
X = 1300-800,
X = 500.
X+800 = 13*5/3 *60,
X+800 = 13*5*20,
X+800 = 65*20,
X+800 = 1300,
X = 1300-800,
X = 500.
Ramesh said:
1 decade ago
Speed of train: 78kn/hr=78*(5/18)=21.67m/sec
Distance=800m
Time=60sec
d=s*t
800+x=21.67*60
x=1300.2-800=500
Distance=800m
Time=60sec
d=s*t
800+x=21.67*60
x=1300.2-800=500
Roobha said:
6 years ago
1km = 1000m,
1hr = 3600sec.
Convert,
Km/hr=m/sec.
= 1000/3600m/sec,
= 5/18m/sec.
1hr = 3600sec.
Convert,
Km/hr=m/sec.
= 1000/3600m/sec,
= 5/18m/sec.
ABDUL WAHAB SHAH said:
6 years ago
Last step:
3(800 + x) = 3900.
2400 + 3x = 3900.
3x = 3900 - 2400.
3x = 1500.
x = 1500/3.
x = 500.
3(800 + x) = 3900.
2400 + 3x = 3900.
3x = 3900 - 2400.
3x = 1500.
x = 1500/3.
x = 500.
(5)
Sarang said:
7 years ago
Distance =speed * time,
D=78km/h*1minute,
D=78*5/18*60.
D=78*.277*60.
D=21.6*60= 1300-800= 500.
D=78km/h*1minute,
D=78*5/18*60.
D=78*.277*60.
D=21.6*60= 1300-800= 500.
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