Train X and Train Y, traveling at their respective constant rates, are

Question

Train X and Train Y, traveling at their respective constant rates, are moving in the same direction along parallel tracks. Initially, Train X is behind Train Y by 18 kilometers, but after 4 hours, Train X is 6 kilometers ahead of Train Y.

Using the information given, identify an answer that could be the speed of Train X and an answer that could be the speed of Train Y, both in kilometers per hour (k/h). Make only two selections, one in each column.

rocky620 · Accepted Answer

Let the speed of train X = a
Let the speed of train Y = b

Initially Train X is 18km behind, but after 4 hours it is 6km ahead.

So, in 4 hours it covered 24kms more than Train Y. Hence we can conclude that Train X's speed is 6km more than that of Train Y.

a-b = 6

Only 54 & 48 satisfy this condition.

Speed of train X = 54
Speed of train Y = 48

pudu · Answer

in 4 hours X covers 24 km. So n 1 hr it covers 6km. Find out option that gives 6 difference between values. Only 54 for X and 48 for Y satisfies.

kuldeepsingh512 · Answer

X= (a+24)/4= (a/4) + 6
Y= (a/4)

So speed of X and Y have diff of 6, the only pair to satisfy this condition is 48 and 54.

Posted from my mobile device

MT1302 · Answer

Key Formula ---->

Distance = Speed * Time

Train X   :

Let Speed = Sx , Time = Tx , Distance = Dx ;   Dx = Sx * Tx

Train Y    :

Let Speed = Sy , Time = Ty , Distance = Dy ; Dy = Sy * Ty

Now translate the lines one by one.

Initially, Train X is behind Train Y by 18 kilometers :

So, Dx = Dy - 18. ....(eqn. 1)

but after 4 hours, Train X is 6 kilometers ahead of Train Y :

After 4 hours means :  Time will be added by 4

=   + 6

+ 4Sx =   + 4Sy + 6

4Sx - 4Sy - 6 =   -

4Sx - 4Sy - 6 = 18 (From equation 1)

4Sx - 4Sy = 24 (Divide this complete euation by 4)

Sx - Sy = 6

From answer choices :  Sx = 54  and  Sy = 48 
Satisfies it.

Hope it helps.

KushagraKirtiman · Answer

Very easy question

Train X covers a distance of 24 kilometers in 4 hours which means = relative speed of x wrt y is 6 greater.

Vx-Vy=6

Only 54 and 48 combination works. So thats the answer.

Honestly dont think a question like this could appear in the exam

Gemmie · Answer

Train X moved faster than Train Y
=> X> Y

In 4 hours, the difference between Train X and Y's travel is 18 + 6 = 24km
=> Difference in speed per hour:  24 \div 4 = 6 
=> X - Y = 6

=> X = 54; Y = 48

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Train X's Speed	Train Y's Speed	Value (k/h)
		44
		48
		49
		54
		57

Train X and Train Y, traveling at their respective constant rates, are

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