Answer: D) 3 Explanation: Given teacher drinks 9 ltrLet number of boys be 'A'.Let number of girls be 'B'.Boy drinks 7 ltr and girl drinks 4 ltrAfter class total water consumed = 42 ltrThen,9 + 7A + 4B = 42=> 7A + 4B = 33By trial and error method,The only integers which satisfy the equation is A = 3 and B = 3Therefore, number of girls in the class = 3.

Answer: B) 420 Explanation: Given total number of students in the class = 21   So each student will have 20 greeting cards to be send or receive (21 - 1(himself))   Therefore, the total number of greeting cards exchanged by the students = 20 x 21 = 420.

Answer: A) Isobutyl bromide Explanation:

The antagonist is the negative or opposing force in a story. It could be a human enemy, or it could be non-human, like an animal or something less tangible, like fear.   The antagonist plays an important role in story development.

Answer: D) Kharagpur Explanation:

Answer: B) 1 Explanation: The pattern follows the palindrome sequence. Here the digits 0 1 4 7 8 5 8 3 6 9    9 6 3 8 5 8 7 4 1 0   0 1 4 7 ... So the next digit in the sequence is 1.

Answer: A) 1 Explanation: In each row,  Sum of 1st two digit number + last two digit number = Middle two digit number i.e., 1st row 15 + 40 = 55 2nd row 46 + 47 = 93 Similarly, 7x + 16 = 87 => x = 1.

Answer: D) Haryana Explanation: Haryana is poised to become the first state to invite all Twitter and Facebook users to interact with the Chief Minister Manohar Lal and contribute towards further improving various services being provided by different departments.