Rationale: Speed downstream = 40 + 20 = 60 kmph
Speed upstream = 40 - 20 = 20 kmph
The answer: (B)
Question: The speed of a boat in still water is 40kmph and the speed of the current is 20kmph. Find the speed downstream and upstream?
Options:
(A) kmph
(B) kmph
(C) kmph
(D) kmph
(E) kmph
Reasoning: 10 books can be rearranged in 10! ways consider the two books taken as a pair then number of favourable ways of getting these two books together is 9! 2!
Required probability = 1/5
Ans: (C)
Question: 10 books are placed at random in a shelf. The probability that a pair of books will always be together is
Options:
(A) 1/9
(B) 1/7
(C) 1/5
(D) 1/6
(E) 1/3
Rationale: Speed = 60 * 5/18 = 50/3 m/sec
Length of the train = speed * time = 50/3 * 6 = 100 m
The answer: (D)
Question: A train running at the speed of 60 km/hr crosses a pole in 6 sec. What is the length of the train?
Options:
(A) 356
(B) 278
(C) 127
(D) 100
(E) 150
Reasoning: Required sum = (23 + 29 + 31 + 37 + 41) = 161
Note: 1 is not a prime number
Ans: (E)
Question: What is the sum of the 1st 5 prime numbers greater than 20?
Options:
(A) 121
(B) 151
(C) 168
(D) 164
(E) 161
Rationale: Total number of votes polled = (4136 + 7636 + 11628) = 23400
So, Required percentage = 11628/23400 * 100 = 50%
The answer: (C)
Question: 3 candidates in an election and received 4136, 7636 and 11628 votes respectively. What % of the total votes did the winning candidate got in that election?
Options:
(A) 45%
(B) 49%
(C) 50%
(D) 59%
(E) 61%
Rationale: Mentally imagine this number as (10 + 2 ) ×× 19 = 190 + 38 = 228.
The answer: (B)

Show your work and conclude with the exact phrasing "Therefore, the final answer is [answer]." where [answer] is just the final number or expression that solves the problem.
user
Question: Find 12 ×× 19
Options:
(A) 238
(B) 228
(C) 208
(D) 277
(E) 101