Answer: D) 1/2 kmph Explanation: Speed in upstream = Distance / Time = 3 x 60/20 = 9 km/hr. Speed in downstream = 3 x 60/18 = 10 km/hr Rate of current = (10-9)/2 = 1/2 km/hr.

Answer: B) K=1 & L=4 Explanation: As per divisibility rule a number is divisible by 6 means it should be divisible by 2 and 3 case 1 : the divisibility rule for 2 is the number should be end with even number in this case R =2 & R=4 case 2 : The divisibility rule for 3 is the sum of numbers should be divisible by 3so if we take option (2) Q=1 & R=4 the sum is 39 if we take option (3) Q=1 & R=2 the sum is 37 So Option (2) is correct 39 is divided by 3

Answer: C) 24min Explanation: Given taps X and Y can fill the tank in 30 and 40 minutes respectively. Therefore,   part filled by tap X in 1 minute = 1/30   part filled by tap Y in 1 minute = 1/40   Tap Z can empty the tank in 60 minutes. Therefore,   part emptied by tap Z in 1 minute = 1/60   Net part filled by Pipes X,Y,Z together in 1 minute = [1/30 +1/40 - 1/60] = 5/120 = 1/24   i.e., the tank can be filled in 24 minutes.

Answer: D) 37 Explanation: Let the number of students in the class be 'x'.Given if 1 is absent rest of people can be divided into 6 equal parts i.e (x-1)/6.........(1)And given if 2 are absent rest of people can be divided into 7 equal parts i.e (x-2)/7.....(2)From (1)&(2), we getx-1/6 = ((x-2)/7) + 1=> x = 37.

Answer: B) 6:5 Explanation:     4:5    3:2   -------=> 12:15:10  12:10 => 6:5

Answer: C) high physiological age Explanation:

Answer: D) Fiber-optic Explanation: Fiber-optic physical or wired connection is the fastest communication connection.

Answer: B) 20 minutes Explanation: Let the total distance to be covered is 84 kms.Time taken to cover the distance without stoppage = 84/42 hrs = 2 hrsTime taken to cover the distance with stoppage = 84/28 = 3 hrs.Thus, he takes 60 minutes to cover the same distance with stoppage.Therefore, in 1 hour he stops for 20 minutes.