Reasoning: Speed = 50*(5/18) m/sec = 125/9 m/sec
Length of Train (Distance) = Speed * Time
(125/9) * 18 = 250 meter
Ans: (C)
Question: A train running at the speed of 50 km/hr crosses a pole in 18 seconds. Find the length of the train.
Options:
(A) 150
(B) 188
(C) 250
(D) 288
(E) 300

Rationale: A's 1 hour work = 1/4;
(B + C)'s 1 hour work = 1/3;
(A + C)'s 1 hour work = 1/2
(A + B + C)'s 1 hour work = (1/4 + 1/3) = 7/12
B's 1 hour work = (7/12 + 1/2) = 1/12
B alone will take 12 hours to do the work.
The answer: (C)
Question: A can do a piece of work in 4 hours; B and C together can do it in 3 hours, which A and C together can do it in 2 hours. How long will B alone take to do it?
Options:
(A) 1/19
(B) 1/11
(C) 1/12
(D) 1/17
(E) 1/14

Reasoning: A
72
This is an alternating addition and subtraction series. In the first pattern, 8 is subtracted from each number to arrive at the next. In the second, 9 is added to each number to arrive at the next.
Ans: (A)
Question: In each series, look for the degree and direction of change between the numbers. In other words, do the numbers increase or decrease, and by how much?
Look at this series: 88, 3, 80, 12, __, 21 ... What number is missing?
Options:
(A) 72
(B) 78
(C) 68
(D) 30
(E) 70

Rationale: D = 110 + 170 = 280 m
S = 36 * 5/18 = 10
T = 280 * 1/10 = 28 sec
The answer: (A)
Question: How long does a train 110 m long traveling at 36 kmph takes to cross a bridge of 170 m in length?
Options:
(A) 28
(B) 16.0
(C) 16.4
(D) 16.8
(E) 16.1

Reasoning: Rate of H = 6 acres/hr
Remaining land to be harvested = 100 - 40 = 60
Rate of H and K = 60/6 = 10 acres/hr
Rate of K = 10 - 6 = 4
Ans: (A)
Question: A farm used two harvesting machines, H and K, to harvest 100 acres of wheat. Harvesting machine H, working alone at its constant rate, harvested 40 acres of wheat in 8 hours. Then harvesting machine K was brought in, and harvesting machines H and K, working together at their respective constant rates, harvested the remaining acres of wheat in 6 hours. Harvesting machine K harvested how many acres of wheat per hour?
Options:
(A)  4
(B)  8
(C)  12
(D)  13
(E)  15

Reasoning: Speed downstream = 50 + 20 = 70 kmph
Speed upstream = 50 - 20 = 30 kmph
Ans: (C)

Question: The speed of a boat in still water is 50kmph and the speed of the current is 20kmph. Find the speed downstream and upstream?
Options:
(A) 40, 68 kmph
(B) 40, 30 kmph
(C) 70, 30 kmph
(D) 40, 60 kmph
(E) 20, 60 kmph