Question

If A + B means - 'A is the mother of B'. A $÷$ B mean - 'A is the brother of B' and A $\times$ B means - 'A is the son of B' and A - B means - 'A is the sister of B' then which of the following means - 'C is the sister of D' ?

• A. D - C
• B. D $\times$ P - C
• C. C - P $÷$ D
• D. P + D $÷$ C
• E. D - P $÷$ C

Answer 1

The correct option is C C - P $÷$ D

Diagram for the alternative (a)
D - C means D is the sister of C
It is clear from the diagram that D is the sister of C but it is not necessary that C is the sister of D. C may also be brother of D. Hence, the alternative (A) does not answer the question.
Diagram for the alternative (b)
$\to D\times P-C$
(1) D $\times$ P means D is the son of P
(2) P - C means P is the sister of C
If C is supposed to be a male then he will be the maternal uncle of D and if C is supposed to a female then she will the maternal aunt of D. Hence, the alternative (B) does not answer the questions.
Diagram for the alternative (c)
$C-P÷D$
(1) C - P means C is the sister of P
(2) P $÷$ D means P is the brother of D
It is clear from the diagram that if P is the brother of D then either D will be a male or a female.If D is a male then C is the sister of D and if D is a female then also C is the sister of D. Hence, the alternative (C) answers the question correctly.
Diagram for the alternative(d)
$P+D÷C$
(1) $P÷D$ means P is the mother of D.
(2) $D÷C$ means D is the brother of C.
It is clear from the diagram that D is the brother of C. So C may be a male or female. Hence, the alternative (D) does not answer the question.
Diagram for the alternative(e)
$D-P÷C$
(1) D - P means D is the sister of P.
(2) $P÷C$ means P is the brother of C.
From the diagram P is brother of C. So C may be a male or a female. Hence, from this it is not clear that C is the sister of D. Hence, this alternative also fails to answer the question. Therefore, (c) is the correct answer.