Verbal Reasoning - Mental Ability Questions

In a family, there are six members A, B, C, D, E and F. 

A and B are a married couple, A being the male member. D is the only son of C, who is the brother of A. E is the sister of D. B is the daughter-in-law of F, whose husband has died. How is F related to A ? 

Select the related word/letters/numbers from the given alternatives:

42:20::64:?

Introducing a man, a woman said, 'He is the only son of my mother's mother." How is the woman related to the man ?  

In the following question, select the related number from the given alternatives.

5 : 124 : : 6 : ?

The following equation is incorrect. Which two signs should be interchanged to correct the equation?

8 + 2 - 40 ÷ 5 x 16 = 44

Look at the series :

3, 7, 24, 11, __, 19, 19,... What number should fill the blank ?

Consider the following information and answer questions based on it.

Six students Lily, Mary, July, Daisy, Rosy and Fairy are sitting in a circle facing each other such that -

1. Mary sits to the immediate right of July.

2. Lily does not sit near Fairy.

3. The student sitting on the immediate left of July, sits to the immediate right of Fairy.

4. Rosy does not sit to the immediate right of Mary.

___ sits to the immediate left of Lily.

In the following question, select the related letter pair from the given alternatives.

FOM : CLJ : : ?  :  ?