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:
2 : 3
4 : 3
6 : 7
9 : 16
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:
112 comments Page 4 of 12.

Kiran.p said:   2 decades ago
It is formula, see below for important formulas.

Problems on Trains - Important Formulas

PARTH said:   2 decades ago
Can someone prove that?

Karunakaran said:   2 decades ago
Let distance = x, a as speed of train a & b as speed of train b

9 x a = x
16 x b= x

9a = 16b

a/b = 16/9, simplify this with square root both up & down we get 4/3 & ratio 4:3.

Ashish said:   2 decades ago
Explain formula used.

SAURABH SUMAN said:   2 decades ago
SIMPLY THEY ARE USING DISTANCE FORMULA DISTANCE=TIME*SPEED

Abhishek said:   2 decades ago
It is a completely wrong answer.

<Case-1> Speed = Distance/Time

(As distance is same, so Speed(S1)= Distance(D)/Time(T1).
Similarly, (S2)= (D)/(T2), Now, (S1)/(S2)=[(D)/(T1)]/[(D)/(T2)]
=[(D)/(T1)]*[(T2)/(D)]
=(T2)/(T1)
So,ratio of speeds is inversely proportional to ratio of times.

<Case-2>

How can (16/9)=(4/3) or (9/16)=(3/4)??? Please Explain???

In Ratio,Proportion and percentage,(9/16)*100 = 56.25%;
But,(3/4)*100 = 75%.

Now, PLEASE EXPLAIN,IS 56.25% = 75% ???

THE CORRECT ANSWER TO THE ABOVE QUESTION IS (16/9) or 16:9.
OR IF WE CONSIDER THE REVERSE RATIO(RECIPROCAL)OF SPEEDS, THEN (9/16) or (9:16).

Vijay said:   2 decades ago
Ishita Narula z correct....

Abhimanini said:   2 decades ago
How can we calculate the time to cover the total distance, for this sum?

Subhendu said:   2 decades ago
@abhisek.

Please be reasonable yaar. Otherwise you will be a laughing stuff to everyone.

Pradeep vishwakarma said:   2 decades ago
Ishita narula is correct. Thank you.


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