Aptitude - Problems on Trains - Discussion
Discussion Forum : Problems on Trains - General Questions (Q.No. 31)
31.
Two, trains, one from Howrah to Patna and the other from Patna to Howrah, start simultaneously. After they meet, the trains reach their destinations after 9 hours and 16 hours respectively. The ratio of their speeds is:
Answer: Option
Explanation:
Let us name the trains as A and B. Then,
(A's speed) : (B's speed) = b : a = 16 : 9 = 4 : 3.
Discussion:
110 comments Page 3 of 11.
Aakash said:
7 years ago
Let's say.
Train A travels 'x' is the distance from Patna with speed 'V1' till the point of meet and
train B travels 'y' is the distance from Patna with speed 'V2' till the point of the meet.
the time taken for them to meet 't' = x/V1= y/V2 ---- (1)
Now Train A will travel 'y' distance that was previously travelled by train 'B' and vice-versa.
As per given info;
y/V1 = 9 and x/V2 = 16.
Taking ratio:
y/V1*V2/x = 9/16.
but from (1) -----> y/x = V1/V2,
=> ( V1/V2)^2 = 9/16.
=> V1:V2 = 3:4.
Train A travels 'x' is the distance from Patna with speed 'V1' till the point of meet and
train B travels 'y' is the distance from Patna with speed 'V2' till the point of the meet.
the time taken for them to meet 't' = x/V1= y/V2 ---- (1)
Now Train A will travel 'y' distance that was previously travelled by train 'B' and vice-versa.
As per given info;
y/V1 = 9 and x/V2 = 16.
Taking ratio:
y/V1*V2/x = 9/16.
but from (1) -----> y/x = V1/V2,
=> ( V1/V2)^2 = 9/16.
=> V1:V2 = 3:4.
(1)
Santosh parmar said:
7 years ago
Thanks all for explaining this.
(1)
Anil said:
6 years ago
Why are getting the square root. Can anyone explain to me?
(1)
Ishu shrivastava said:
6 years ago
Solving the eqns..
D=(v1+v2)t ---------> 1
D=(t+9)v1---------> 2
D=(t+16)v2---------> 3.
Putting the value of t from eq 1 in eq 2 & 3 then taking all the term having D on one side and then taking ratio of eq.2 & 3.
And we will get v1/v2=√16/√9= 4/3.
D=(v1+v2)t ---------> 1
D=(t+9)v1---------> 2
D=(t+16)v2---------> 3.
Putting the value of t from eq 1 in eq 2 & 3 then taking all the term having D on one side and then taking ratio of eq.2 & 3.
And we will get v1/v2=√16/√9= 4/3.
(1)
Ahaji Victor said:
6 years ago
The correct answer is 4/3 because in the question both trains meets with each other before the now covered their remaining distance in 9hr and 16hrs respectively.
(1)
Gayathri said:
2 years ago
Thanks everyone for explaining the answer.
(1)
Bhargav said:
2 decades ago
Speed = Distance/Time; Then how will you write root of time?
Vinod said:
2 decades ago
How can you calculate speed as the square-root of time?
Kiran.p said:
2 decades ago
PARTH said:
2 decades ago
Can someone prove that?
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