There are 10 stations between A and B . If 4 more stations added, how many more tickets will be required (if one ticket is issued for every one-way tour).

Returning journey ticket for one station to the other station will be counted under the ongoing journey for the other station.

Number of stations = 10 + 2 = 12

So, number of tickets required for each station = 11

Hence, total number of tickets required = 12 × 11 = 132

When four more stations are added, then total number of tickets required = 16 × 15 = 240

Now, required number of tickets = 240 – 132 = 108