Answer: C) 042 Explanation: From all the hints given,  only 042 satisfies and it unlocks the key.

Answer: A) Repetitious Explanation: Here the given words, sullen and moody are synonyms to each other which means that gloomy, resentful. Similarly, repetitious and monotonous are synonyms to each other which means dull, tedious.   Hence, Sullen : moody :: monotonous : repetitious.

Answer: D) 2.25 % Explanation: SP of each car is Rs. 404415, he gains 15% on first car and losses 15% on second car. In this case, there will be loss and percentage of loss is given by = [(profit%)(loss%)]/100 = (15)(15)/100 % = 2.25%

Answer: A) Electrons orbit around the nucleus Explanation: Electrons orbit around the nucleus is correct about them.

Answer: B) Either a or b follows Explanation: Clearly, either the traffic signals should be made to function properly or traffic personnel should be deployed to guide vehicular movement in the right way. So either I or II follows.

Answer: A) West Bangal Explanation: BidhanNagar in Kolkata, West Bangal is popularly known as Salt Lake City.

8 S on SS means 8 Sides on a Stop Sign. This is one type of Letter Equations which are well known phrases or facts where the key words have been replaced with the first letter of that word. These are often in the form of an equation, which contain a number, an = sign and the rest of the obscured phrase or fact.   Some more of them are :: 90 D in a RA 26 L of the A  12 S of the Z.

Answer: B) 2k1k2/k1+k2 Explanation: We know that,   The equivalent K =  L1 + L2L1K1+L2K2   where L1 & L2 are plate1 & Plate2 thicknesses, K1 & K2 are coefficient thermal conductivity of plate1 & Plate2 respectively.   But here L1 = L2 = L (say)   Then K = L+L/(L/K1 + L/K2)  =  2K1K2K1+K2