Answer: D) 360 mts Explanation: Speed of the Train K is given by s = d/t = 240/20 = 12 m/sDistance covered by Train K in 50 seconds = 12 x 50 = 600 mts.But it crosses Train L in 50 seconds Therefore, the length of the Train L is = 600 - 240 = 360 mts.

Answer: C) 75 Explanation: Here in the given series, it follows a pattern that   77 + 2 = 79   79  - 3 = 76   76 + 5 = 81   81 -  7 = 74   74 + 11 = 85   Consecutive adding and subtracting of prime numbers.   So the wrong number in the given series is 75.

Answer: B) 1/2 Explanation: We know that: When one card is drawn from a pack of 52 cards The numbers of possible outcomes n(s) = 52 We know that there are 26 red cards in the pack of 52 cards⇒ The numbers of favorable outcomes n(E) = 26 Probability of occurrence of an event: P(E)=Number of favorable outcomes/Numeber of possible outcomes=n(E)/n(S) ∴ required probability = 26/52 = 1/2.

Answer: A) 400 m Explanation: Speed = 78 x 5/18 = 65/3 m/sec.Time = 1 min = 60 sec.Let the length of the train be x meters.Then, (900 + x)/60 = 65/3x = 400 m.

A number of possible explanations for why manhole covers are round include :   1. A round manhole cover cannot fall through its circular opening, whereas a square, rectangular, or oval manhole cover could fall in if it were inserted diagonally in the hole. 2. Circular covers don’t need to be rotated or precisely aligned when placing them on the opening. 3. A round manhole cover is easily moved and rolled. 4. Human beings have a roughly circular cross-section. 5. Round tubes are the strongest shape against the compression of the earth around them, so the cover of the tube would naturally be round as well. 6. It’s easier to dig a circular hole.

Answer: C) 28 hrs Explanation: 1/K + 1/L + 1/M = 1/8 (Given)Also given that K = 2L and L = 2M=> 1/2L + 1/L + 2/L = 1/8=> (1 + 2 + 4)/2L = 1/8=> 2L/7 = 8=> L = 28 hours.

Answer: C) 5/9 Explanation: Here n(S) = 6 x 6 = 36 E={(1,2),(1,5),(2,1),(2,4),(3,3),(3,6),(4,2),(4,5),(5,1),(5,4),(6,3) ,(6,6),(1,3),(2,2),(2,6),(3,1),(3,5), (4,4),(5,3),(6,2)} => n(E)=20 Required Probability n(P) = n(E)/n(S) = 20/36 = 5/9.

Answer: C) Rs. 7000 Explanation: Let the sum be Rs. S.(S x 18 x 2)/100 - (S x 12 x 2)/100 = 840 => 36S/100 - 24S/100 = 840 => 12S/100 = 840 => S = 7000.