Reasoning: P(B|A) = P(A âˆª B)/P(A)
P(B|A) = (6/15)/(2/15) = 3.
Ans: (C)
Question: If P(A) = 2/15, P(B) = 4/15, and P(A âˆª B) = 6/15 Find P(B|A)
Options:
(A) 1/2
(B) 2/3
(C) 3
(D) 4/5
(E) 4/7


Reasoning: Speed downstream = d/t = 85/(2 1/2) = 34 kmph
Speed upstream = d/t = 45/(2 1/2) = 18 kmph
The speed of the stream = (34 - 18)/2 = 8 kmph
Ans: (D)
Question: A man rows his boat 85 km downstream and 45 km upstream, taking 2 1/2 hours each time. Find the speed of the stream?
Options:
(A) 2 kmph.
(B) 4 kmph.
(C) 5 kmph.
(D) 8 kmph.
(E) 7 kmph.


Reasoning: Average of 20 numbers = 0
Sum of 20 numbers = (0 * 20) = 0
It is quite possible that 19 of these numbers may be positive and if their sum is a, then 20th number is (-a).
Ans: (D)
Question: The average of 20 numbers is zero. Of them, at the most, how many may be greater than zero?
Options:
(A) 87
(B) 15
(C) 17
(D) 19
(E) 16


Reasoning: Work done by A in 4 days = 4/5
Remaining work = 1/5
Work done by both A and B in one day = 1/5 + 1/10 = 3/10
Remaining work = 1/5 * 10/3 = 2/3 days.
Ans: (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: A and B can do a work in 5 days and 10 days respectively. A starts the work and B joins him after 4 days. In how many days can they complete the remaining work?
Options:
(A) 6 days
(B) 2/3 days
(C) 8 days
(D) 3 days
(E) 9 days