Answer: C) 1.5 kmph Explanation: 72 --- 9 ? ---- 1 => Down Stream = 8 45 ---- 9 ? ---- 1 => Up Stream = 5 Speed od current S = ? S = (8 - 5)/2 = 1.5 kmph.

Answer: B) 30 years Explanation: Let Karan’s present age be x years and Shiva’s present age be y years.Then, according to the first condition,x - 10 = 3(y - 10) or x - 3y = - 20 ..(1) Now, Karan’s age after 10 years = (x + 10) yearsShiva’s age after 10 years = (y + 10)(x + 10) = 2 (y + 10) or x - 2y = 10 ..(2) Solving (1) and (2), we get x = 70 and y = 30Karan’s age = 70 years and Shiva’s age = 30 years.

Answer: A) 68 kmph Explanation: Let the speed of the faster train be 'X' kmph, Then their relative speed= X - 48 kmphTo cross slower train by faster train, Distance need to be cover = (400 + 600)m = 1 km. and Time required = 180 sec = 180/3600 hr = 1/20 hr.Time = Distance/Speed => 1/20 = 1/(x-48)X = 68 kmph

Answer: B) Rs.17,500 Explanation: Let’s assume John bought the laptop for Rs. 100He then sells it to Mark at a loss of 20% => Rs. 80,Who consequently sells it to Kevin at a profit of 25% =>  Rs. 100Then, Kevin sells it back to Mark for Rs. 90 (Rs.4.50 for every Rs. 5 that he had paid initially), so he suffers a loss of Rs. 10Therefore, for Rs. 100 there is a loss of Rs. 10,Then for Rs. 1,75,000 there will be a loss of Rs. 17,500.

Answer: B) 30 min Explanation: Distance travelled by Ramu = 45 x 4 = 180 km Somu travelled the same distance in 6 hours. His speed = 180/6 = 30 km/hr Hence in the conditional case, Ramu's speed = 45 - 9 = 36 km/hr and Somu's speed = 30 + 10 = 40km/hr. Therefore travel time of Ramu and Somu would be 5 hours and 4.5 hours respectively. Hence difference in the time taken = 0.5 hours = 30 minutes.

Answer: B) 4 : 3 Explanation: Let us name the trains as A and B. Then, (A's speed) : (B's speed) = √b : √a = √16 : √9 = 4:3

Answer: D) 4 3/8 km Explanation: Relative Speed = 5 ¾ - 4 ½ = 1 ¼ Time = 3 ½ h. Distance = 5/4 x 7/2 = 35/8 = 4 3/8 km.