Quantity I: A can complete a task in 15 days, while B can do it in 12 days. A worked alone for the first 5 days and then left. B and C together finished the remaining work in 4.8 days. How long will it take C to complete the work on his own? Quantity II: The current age ratio of A to B is 3:2, and the average age of A, B, C, and D is 15 years. B’s age is 2.5 years less than the average of A and B’s ages, and C is older than
D. What is C’s current age?

Answer: D Quantity I: Time taken by A alone to complete the work = 15 days Time taken by B alone to complete the work = 12 days Part of work done by A alone in 1 day = 1/15 So, part of work done by A alone in 5 days = 5/15 = 1/3 Remaining part of work = 2/3 Time taken by B and C together to complete remaining work = 4.8 days So, time taken by B and C together to complete the whole work So, = 4.8 * 3/2 = 7.2 days So, time taken by C alone to complete the whole work = 18 days Quantity II: Let present ages of A and B are ‘3x’ and ‘2x’ respectively. So, [(3x + 2x)/2] – 2x = 2.5 x = 5 Present age of A and B are 15 years and 10 years, respectively. Since, average of present ages of A, B, C and D = 15 years So, (15 + 10 + C + D)/4= 15 C + D = 35 Since, C is older than D. So, present age of C ≥ 18 years. Hence, Quantity I ≤ Quantity II