Answer: B) 40 yrs Explanation: Let the present ages of Ajay and Vijay be 'A' and 'V' years respectively. => A - 8 = 4/3 (V - 8) and A + 8 = 6/5 (V + 8) => 3/4(A - 8) = V - 8 and 5/6(A + 8) = V + 8 V = 3/4 (A - 8) + 8 = 5/6 (A + 8) - 8 => 3/4 A - 6 + 8 = 5/6 A + 20/3 - 8 => 10 - 20/3 = 10/12 A - 9/12 A => 10/3 = A/12 => A = 40.

Answer: D) 12% p.a. Explanation: If the interest earned is 25% more than the earlier interest then the rate of interest also should be 25% higher than the earlier rate. Let the earlier rate of interest be x%. Now it will be (x + 3)% % increase = (x + 3) - x/x * 100 = 25=> x = 12%

Answer: B) 6 hrs Explanation: Suppose A, B and C take x, x/2 and x/3 respectively to finish the work. Then, (1/x + 2/x + 3/x) = 1/2 6/x = 1/2 => x = 12 So, B takes 6 hours to finish the work.

Answer: D) ²²C₁₀ - 1 Explanation: The total number of ways of forming the group of ten representatives is ²²C₁₀. The total number of ways of forming the group that consists of no seniors is ¹⁰C₁₀ = 1 way The required number of ways = ²²C₁₀ - 1

Answer: A) 45 Explanation: 16200 = 23×34×52   A perfect cube has a property of having the indices of all its prime factors divisible by 3.   Required number = 32×5 = 9x5 = 45.

Answer: B) 1 hr 20 min Explanation: Let the distance and original speed be 'd' km and 'k' kmph respectively. d/0.8k - d/k = 20/60 => 5d/4k - d/k = 1/3 => (5d - 4d)/4k = 1/3 => d = 4/3 k Time taken to cover the distance at original speed = d/k = 4/3 hours = 1 hour 20 minutes.

Answer: B) 480 lit Explanation: 1/k - 1/20 = -1/24 k = 120 120 x 4 = 480 Therefore, the capacity of the cistern is 480 liters.

Answer: A) 20% p.a Explanation: Rs.1440 - 1200 = Rs.240 is the interest on Rs.1200 for one year. Rate of interest = (100 x 240) / (1200) = 20% p.a