question:There are 10person among whom 2are brother. The total no.of ways in which these persons can be seated around a round table so that exactly 1person sit between the brothers, is equal to?
Options:
(A) 4!*2!
(B) 7!*2!
(C) 6!*1!
(D) 2!*1!
(E) 5!*1!
answer:(B)
Stream of consciousness:Total number of ways = 7!*2!.

question:A committee has 5 men and 6 women. What are the number of ways of selecting a group of eight persons?
Options:
(A) 165
(B) 185
(C) 205
(D) 225
(E) 245
answer:(A)
Stream of consciousness:Total number of persons in the committee = 5 + 6 = 11
Number of ways of selecting group of eight persons = C = C = (11 * 10 * 9)/(3 * 2) = 165 ways.

question:The speed of a train is 90 kmph. What is the distance covered by it in 10 minutes?
Options:
(A) 15
(B) 66
(C) 77
(D) 52
(E) 42
answer:
(A)
Stream of consciousness:90 * 10/60 = 15 kmph