Rationale: One day work of A and B = 1/2
One day work of B and C = 1/6
One day work of C and A = 1/8
2(A + B + C) = 1/2 + 1/6 + 1/8
2(A + B + C) = 19/24
(A + B + C) = 19/48
Number of days required = 48/19 days.
The answer: (B)
Question: A and B can do a work in 2 days, B and C in 6 days and C and A in 8 days. In how many days will the work be completed, if all three of them work together?
Options:
(A) 12/28
(B) 48/19
(C) 16/48
(D) 18/48
(E) 12/64

Reasoning: Work done by X in 1 day = 1/18
Work done by Y in 1 day = 1/15
Work done by Y in 5 days = 5/15 = 1/3
Remaining work = 1 – 1/3 = 2/3
Number of days in which X can finish the remaining work = (2/3) / (1/18) = 12
Ans: (A)
Question: X can finish a work in 18 days. Y can finish the same work in 15 days. Yworked for 5 days and left the job. how many days does X alone need to finish the remaining work?
Options:
(A) 12
(B) 5
(C) 6
(D) 8
(E) 9

Rationale: D = 500 + 230 = 730
S = 44 * 5/18 = 12 mps
T = 730/12 = 61 sec
The answer: (D)
Question: A train 500 meters long is running with a speed of 44 kmph. The time taken by it to cross a tunnel 230 meters long is?
Options:
(A) 287 sec
(B) 288 sec
(C) 48 sec
(D) 61 sec
(E) 17 sec

Reasoning: Each of the numbers except 28, is a multiple of 3.
Ans: (D)
Question: Select Odd number:
6, 9, 15, 21, 24, 28, 30
Options:
(A) 20
(B) 21
(C) 24
(D) 28
(E) 30

Rationale: P(at least one graduate) = 1 - P(no graduates)
(6 * 5 * 4)/(10 * 9 * 8) = 5/6
The answer: (D)
Question: Out of 10 persons working on a project, 4 are graduates. If 3 are selected, what is the probability that there is at least one graduate among them?
Options:
(A) 5/9
(B) 5/4
(C) 5/1
(D) 5/6
(E) 5/2

Rationale: 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
The answer: (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