Answer: B) 5/36 Explanation: The two events mentioned are independent. The first roll of the die is independent of the second roll. Therefore the probabilities can be directly multiplied. P(getting first 4) = 1/6 P(no second 6) = 5/6 Therefore P(getting first 4 and no second 6) = 1/6 x 5/6 = 5/36

Answer: D) 8:3 Explanation: Let the speed of the boat upstream be p kmph and that of downstream be q kmph   Time for upstream = 8 hrs 48 min = 845hrs   Time for downstream = 4 hrs   Distance in both the cases is same.   => p x  845= q x 4   => 44p/5 = 4q   => q = 11p/5    Now, the required ratio of Speed of boat : Speed of water current   = q+p2:q-p2   => (11p/5 + p)/2  : (11p/5 - p)/2   => 8 : 3

Answer: C) 25 Explanation: a+b=5   ...(1)    and    3a+2b=20 ...(2)   Multiplying (1) by 2 and subtracting from (2), we get : a=10.   Putting a=10 in (1), we get : b=-5   Therefore,   (3a+b) = 3 x 10+(-5)=30-5=25.

Answer: C) 109 Explanation: From given data, R : M = 5 : 7 M : A = 5 : 7 R : M : A = 25 : 35 : 49 25 + 35 + 49 = 109

Answer: D) 140 mts Explanation: Speeds of two trains = 30 kmph and 58 kmph => Relative speed = 58 - 30 = 28 kmph = 28 x 5/18 m/s = 70/9 m/s Given a man takes time to cross length of faster train = 18 sec   Now, required Length of faster train = speed x time = 70/9  x  18 = 140 mts.

Answer: A) 215 Explanation: Since each ring consists of six different letters, the total number of attempts possible with the three rings is = 6 x 6 x 6 = 216. Of these attempts, one of them is a successful attempt.   Maximum number of unsuccessful attempts = 216 - 1 = 215.

Answer: A) 18 Explanation: (300 – 101)/11 = 199/11 = 18 1/1118 Numbers.

Answer: B) 180 Explanation: 4 x 27 x 3125 = 22 × 33 × 55 ;   8 x 9 x 25 x 7 = 23 × 32 × 52 × 7   16 x 81 x 5 x 11 x 49 = 24 × 34 × 5 × 11 × 72   H.C.F = 22 × 32 × 5 = 180.