q: From a Group of 9 People, Including George and Nina, 4 people are to be selected at random to work on a certain project. What is the probability that 4 people selected will include George but not Nina
Options:
(A) 5/56
(B) 9/56
(C) 15/56
(D) 35/120
(E) 25/56
a: OK... Number of ways of selecting 4 people out of 9 people = 9C4
In the three members George will always be there in the team. At this step we have vacancy for 3 more members and 8 members are available. Nina cannot be there in the team. So 3 members have to be selected and the number of available members = 8 - Nina = 7
Number of ways to form a 4 member team that includes George and excludes Nina = 7C3
Probability = 7C3/9C4 = 35/120
The answer is (D).

q: Two trains are traveling on parallel tracks in the same direction. The faster train travels at 110 miles per hour, while the slower train travels at 100 miles per hour. At 1 o'clock the faster train is 40 miles behind the slower one. How far apart are the two trains at 7 o'clock?
Options:
(A) 20 miles
(B) 80 miles
(C) 90 miles
(D) 120 miles
(E) 400 miles
a: OK... Answer = A. 20 miles
Relational speed = 110 - 100 = 10 miles per hour
In 6 hours, difference = 10 * 6 = 60 miles
Fast train trailing 40 miles, so effective difference = 60 - 40 = 20 miles
The answer is (A).

q: There are 10 female and 15 male in a work place. In how many ways can a person can be selected?
Options:
(A) 20
(B) 15
(C) 18
(D) 40
(E) 25
a:
OK... No of ways = 10+ 15 = 25
The answer is (E).