Question

There are 15 buses running between Delhi and Mumbai. In how many ways can a man go to Mumbai and return by a different bus?

• A. 280
• B. 310
• C. 240
• D. 210
• E. None of these

Answer 1

The correct option is D 210

The first event of going from Delhi to Mumbai can be performed in 15 ways as he can go by any of the 15 buses. But the event of coming back from Mumbai can be performed in 14 ways (a different bus is to be taken). Hence, both the events can be performed in $15\times 14=210ways.$