How to speak fast and understand native speakers

If eight persons are to address a meeting, then the number of ways in which a specified speaker is to speak before another specified speaker, is

There are 10 girls and 8 boys in a class room including Ms. Rani and Radha. A list of speakers consisting of 8 girls and 6 boys has to be prepared. Mr. Ravi refuses to speak if Ms. Rani is a speaker. Ms. Rani refuses to speak if Ms. Radha is a speaker . The number of ways the list can be prepared is

Ten speakers including A, B, C speak at a function. Given that A speaks before B, B speaks before C, the chance that A, B, C are adjacent speakers is (A) 1 6 (B) 5 (C) 2 5 (D) 15 A B

Ten speakers including A ,B ,C speak at a function.Given that A speaks before B,B speaks before C, the chance that A,B,C are adjacent speakers is