Question

Rajdhani express going from Bombay to Delhi stops at 5 intermediate stations. 10 passengers enter the train during the journey with tickets of two classes. The number of different sets of tickets they may have is

• A. ${{}^{15}C}_{10}$
• B. ${{}^{20}C}_{10}$
• C. ${{}^{30}C}_{10}$
• D. None of these

Answer 1

The correct option is C ${{}^{30}C}_{10}$

For a particular class total number of different tickets from first intermediate station = 5
Similarly number of different tickets from second intermediate station = 4
So total number of different tickets
= 5 + 4 + 3 + 2 + 1 = 1
And same number of tickets for another class.
$\Rightarrow$ total number of different tickets = 30 and number of selection = ${{}^{30}C}_{10}$