Answer: A) Total internal reflection Explanation: A periscope is an optical instrument that uses a system of prisms, lenses, or mirrors to reflect images through a tube.       Light from a distant object strikes the top mirror and is then reflected at an angle of 90 degrees down the periscope tube. At the bottom of the periscope, the light strikes another mirror and is then reflected into the viewer’s eye.   Hence, A periscope works by the principle of Total internal reflection.

Answer: B) A = 30000 B = 40000 C = 48000 Explanation: Compound ratio of A:B:CA:B = 3:4B:C = 5:6----------A:B:C = 15:20:24 We can divide Rs.118000 in this ratio. Share of A = 15/59 x 118000 = 30000 Share of B = 20/59 x 118000 = 40000 Share of C = 24/59 x 118000 = 48000

Answer: D) 5 minutes Explanation: Let the total capacity of tank be 90 liters.Capacity of tank filled in 1 minute by K = 3 liters.Capacity of tank filled in 1 minute by L = 15 liters.Therefore, capacity of the tank filled by both K and L in 1 minute = 18 liters.Hence, time taken by both the pipes to overflow the tank = 90/18 = 5 minutes.

Answer: B) 15 Explanation: Given when she sells at Rs. 160 for 20 articles, she get 40% loss.   Then, to get 20% profit selling at Rs. 240 for let 'P' articles   => 1602060=240p120   => 120 x 160 x P = 20 x 70 x 240   => P =  15 articles.

Answer: C) rsurts Explanation: The series rtus/rtus/rtus/rtus. Thus, the pattern 'rtus' is repeated.

Answer: A) 72 km Explanation: Rate of her upstream = 12/2.5 = 4.8 km/hr Then, ATQ Rate of downstream = 4.8 x 3 = 14.4 km/hr   Hence, the distance she covers downstream in 5 hrs = 14.4 x 5 = 72 kms.

Answer: D) 117 days Explanation: K's work in a day(1st day) = 1/30L's work in a day(2nd day)= -1/60(demolishing)hence in 2 days, combined work= 1/30 - 1/60 =1/60since both works alternatively, K will work in odd days and L will work in even days.1/60 unit work is done in 2 days58/60 unit work will be done in 2 x 58 days = 116 daysRemaining work = 1-58/60 = 1/30Next day, it will be K's turn and K will finish the remaining 1/30 work.hence total days = 116 + 1 = 117.

Answer: A) The conference was only supposed to be an hour; however, it ran for nearly two and half hours. Explanation: The correct punctuated sentence is A The conference was only supposed to be an hour; however, it ran for nearly two and half hours.