(Ans). (C)
(Question). There are 10 students named alphabetically from A to J. What is the Probability that A and D do not sit together if all 10 sit around a circular table?
Options:
(A) 2/9
(B) 2/5
(C) 7/9
(D) 4/5
(E) 8/9
(CoT). Number of students = 10
Number of ways 10 students can sit around a circular table = (10 - 1)! = 9!
Number of ways A and D sit together (consider A and D as one entity) = (9 - 1)! = 8! * 2
Number of ways A and D do not sit together = 9! - (8! * 2)
Probability = (9! - (8! * 2))/9! = 1 - 2/9 = 7/9

(Ans). (B)
(Question). A train 300 m long is running at a speed of 99 km/hr. In what time will it pass a bridge 195 m long?
Options:
(A) 17
(B) 18
(C) 19
(D) 20
(E) 21
(CoT). Speed = 99 * 5/18 = 55/2 m/sec
Total distance covered = 300 + 195 = 495 m
Required time = 495 * 2/55 = 18 sec

(Ans). (A)
(Question). What is the next number of the following sequence.
8, 8, 6, 2,.... ?
Options:
(A) -4
(B) -5
(C) -6
(D) -7
(E) -8
(CoT). 8-(2*0) = 8
8-(2*1) = 6
6-(2*2) = 2
2-(2*3) = -4

(Ans). (E)
(Question).
The average of ten numbers is 210. The average of first five numbers is 40 and the average of last four numbers is 200. What is the middle number?
Options:
(A) A) 200
(B) B) 2000
(C) C) 800
(D) D) 2100
(E) E) 1100
(CoT). The total of ten numbers = 10X210 = 2100
The total of first 5 and last 4 numbers is = 5 X 40+4 X 200 = 1000
So, the middle number is (2100 - 1000 ) = 1100