30 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 choice from the following answers:
A) 625 B) 870 C) 576 D) 676 E) 700
we can go in any bus out of the 30 buses.   Hence He can go in 30 ways.   Since we can not come back in the same bus that he used for travelling,   we can return in 29 ways.   Total number of ways = 30 x 29 = 870   ANSWER:870
<result>B</result>
30 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?