15 buses are running between two places P and Q. In how many ways can a person go from P to Q and return by a different bus? Choose the correct option.
A) 210 B) 320 C) 150 D) 220 E) 100
we can go in any bus out of the 15 buses.   Hence He can go in 15 ways.   Since we can not come back in the same bus that he used for travelling,   we can return in 14 ways.   Total number of ways = 15 x 14 = 210   210NSWER:210
<result>A</result>
15 buses are running between two places P and Q. In how many ways can a person go from P to Q and return by a different bus?