Question: A can do a piece of work in 3 hours; B and C together can do it in 2 hours, which A and B together can do it in 2 hours. How long will C alone take to do it?
Options:
(A) 2hours
(B) 5hours
(C) 6hours
(D) 4hours
(E) 3hours
Ans: (E)
CoT: A's 1 hour work = 1/3;
(B + C)'s 1 hour work = 1/2;
(A + B)'s 1 hour work = 1/2
(A + B + C)'s 1 hour work = (1/3 + 1/2) = 5/6
C's 1 hour work = (5/6 - 1/2) = 1/3
C alone will take 3 hours to do the work.
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Question: A is the son of C; C and Q are sisters; Z is the mother of Q and P is the son of Z. Which of the following statements is true?
Options:
(A) P and A are cousins
(B) P is the maternsl uncle of A
(C) Q is the maternal grandfather of A
(D) C and P are sisters
(E) none
Ans: (B)
CoT: P is the maternsl uncle of A
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Question: A teacher has to choose the maximum different groups of three students from a total of six students. Of these groups, in how many groups there will be included in a particular student?
Options:
(A) 6
(B) 8
(C) 10
(D) 12
(E) 15
Ans: (C)
CoT: If students are A, B, C, D, E and F; we can have 6C3 groups in all. However, if we have to count groups in which a particular student (say A) is always selected we would get 5C2 = 10 ways of doing it.
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