Algebra
Aptitude

 Back to Questions
Q.

There are 10 stations on a railway line. The number of different journey tickets that are required by the authorities is:

 A.

92

 B.

90

 C.

91

 D.

None of these

 Hide Ans

Solution:
Option(B) is correct

From a certain station, there will be a ticket for each of the other 9 stations and there are 10 stations on the railway line.

The number of different journey tickets $=10×9=90$


(4) Comment(s)


YueRock
 ()

But the ticket price should be the same between 1-2 and 2-1 right? Wouldn't that be 10C2?



Pragya
 ()

solution by permutation: 10 P 2 = 90



Parul
 ()

m not getting dis.. can u help me plz


Deepak
 ()

Lets say there are 10 stations viz 1, 2, 3,4, 5, 6, 7, 8, 9, 10.

Now from station 1 you may go to station 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10. Thus total of 9 tickets are possible.

Similarly from station 2 you may go to station 1, 2, 3, 4, 5, 6, 7, 8, 9, 10. So total of 9 tickets are possible in this case too.

Similarly from every station you may go to every other station and 9 tickets are needed in every such case.

There are 10 such stations so total of $10*9$ tickets are possible/required by authorities.