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On a railway there are 20 stations. The ...

On a railway there are 20 stations. The number of different tickets required in order that it may be possible to travel from every station to every station is

A

210

B

225

C

196

D

105

Text Solution

Verified by Experts

The correct Answer is:
A
Number of different tickets
=20+19+18+17+ . . .+3+2+1=210
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