Reasoning: Bunuel, I'm also a little confused with the number of arrangements of n distinct objects in a circle. Why is it given by (n-1)!. In theveritasanswer they say:answer E (4040), should be the number of ways to arrange all 6 without the seating restriction given. Is this incorrect?
Ans: (C)
Question: At a meeting of the 6 Joint Chiefs of Staff, the Chief of Naval Operations does not want to sit next to the Chief of the National Guard Bureau. How many ways can the 6 Chiefs of Staff be seated around a circular table?
Options:
(A) 120
(B) 480
(C) 4040
(D) 2520
(E) 5040
Rationale: Left After 1st stroke = 1/2
Left After 2nd stroke = 1/2 * 1/2 = 1/4
Left After 3rd stroke = 1/2 * 1/4 = 1/8
Left After 4th stroke = 1/2 * 1/8 = 1/16
Left After 5th stroke = 1/2 * 1/16 = 1/32
Left After 6th stroke = 1/2 * 1/32 = 1/64
So removed = 1- 1/64 = 63/64
The answer: (A)
Question: If 1/2 of the air in a tank is removed with each stroke of a vacuum pump, what fraction of the original amount of air has been removed after 6 strokes ?
Options:
(A) 63/64
(B) 7/8
(C) 1/4
(D) 1/8
(E) 1/16
Reasoning: A's 1 hour work = 1/4;
(B + C)'s 1 hour work = 1/3;
(A + B)'s 1 hour work = 1/2
(A + B + C)'s 1 hour work = (1/4 + 1/3) = 7/12
C's 1 hour work = (7/12 - 1/2) = 1/12
C alone will take 12 hours to do the work.
Ans: (A)
Question: A can do a piece of work in 4 hours; B and C together can do it in 3 hours, which A and B together can do it in 2 hours. How long will C alone take to do it?
Options:
(A) 12hours
(B) 10hours
(C) 6hours
(D) 8hours
(E) 4hours
Rationale: P(A|B) = P(A B)/P(B)
P(A|B) = (11/15)/(4/15) = 11/4.
The answer: (A)
Question: If P(A) = 2/15, P(B) = 4/15, and P(A B) = 11/15 Find P(A|B)
Options:
(A) 11/4
(B) 2/3
(C) 3/2
(D) 4/5
(E) 4/7
Reasoning: Speed = 63 * 5/18 = 35/2 m/sec
Time taken = 210 * 2/35 = 18 sec
Ans: (D)
Question: A train 210 m long, running with a speed of 63 km/hr will pass a tree in?
Options:
(A) 22 sec
(B) 16 sec
(C) 17 sec
(D) 18 sec
(E) 12 sec
Reasoning: Let the average after 7th inning = x
Then average after 16th inning = x - 3
\inline
n_jvn herefore 16(x-3)+87 = 17x
\inline
n_jvn herefore x = 87 - 48 = 39
Ans: (A)
Question: A batsman makes a score of 87 runs in the 17th inning and thus increases his average by 3. Find his average after 17th inning?
Options:
(A) 39
(B) 88
(C) 3
(D) 7
(E) 62