Answer: D) 50 years Explanation: Let Rajan's present age be 'x' years.=> Then his daughter's present age is = x/3 years.His mother's present age = 13x/9 yearsNow, according to the question,x + x/3 + 13x/9 = 125=> x = 125x9/25 = 45Therefore, required difference = 13x/9 - x/3 = 13x - 3x/9 = 10x/9=> 10 x 45/9 = 50 years.

Answer: B) 4 kmph Explanation: Let the distance in one direction = k kms Speed in still water = 4.5 kmph Speed of river = 1.5 Hence, speed in upstream = 4.5 - 1.5 = 3 kmph Speed in downstream = 4.5 + 1.5 = 6 kmph Time taken by Rajesh to row upwards = k/3 hrs Time taken by Rajesh to row downwards = k/6 hrs Now, required Average speed =Total distanceTotal speed = 2kk3 + k6 = 2k x 186k + 3k = 4 kmph    Therefore, the average speed of the whole journey = 4kmph.

Answer: D) All the above Explanation: Answer for What City has No People can be any of these words which has city in it like Velocity, Elasticity or Electricity. In general the answer for the riddle What City has No People is Electricity.

Answer: A) T(2^50) Explanation: Let initial thickness of the paper be 'T'after first fold it will be '2T' = 21Tafter second fold it will be '4T' = 22T after 50th fold it will be T x (250T)

Answer: B) 10 Explanation: Raj Tarun's age = 0 when he was born.Then, given his brother is 6 years old.Then his father is 6 + 32 = 38 when Raj Tarun was bornAnd his mother is 3 years yonger than his father => so his mother was 35 years old when Raj Tarun was bornand his sister is 25 year younger than his mother so Raj Tarun's sister was 10 years old when Raj Tarun was born.

Answer: C) 1425/18 min Explanation: 55 min. spaces are covered in 60 min.60 min. spaces are covered in ((60/55) x 60) min = 720/11 min.Loss in 65 min. = (720/11 - 65 ) = 5/11Loss in 24 hrs = (5/11 x 1/65 x 24 x 60)min = 1440/143 min.

Palm tree.

Answer: B) 60 Explanation: We know that, ● Each digit has a fixed position called its place. ● Each digit has a value depending on its place called the place value of the digit. ● The face value of a digit for any place in the given number is the value of the digit itself ● Place value of a digit = (face value of the digit) × (value of the place).   Hence, the place value of 6 in 64 = 6 x 10 = 60.