The current erection cost of a structure is Rs. 13,200. If the labour wages per day increase by 1/5 of the current wages and the working hours decrease by 1/24 of the current period, then the new cost of erection in Rs. is A. 16,500 B. 15,180 C. 11,000 D. 10,120

GATE 2013 · General Aptitude · Work Time · medium

Answer: New cost of erection = Rs. 15,180

1. Compute wage scaling factor: Wage increase = 1/5. New wage factor = 1 + 1/5 = 6/5.
2. Compute hour scaling factor: Hour decrease = 1/24. New hour factor = 1 - 1/24 = 23/24.
3. Apply both factors to original cost: new_cost = 13,200 * (6/5) * (23/24) = 13,200 * (6 * 23) / (5 * 24) = 13,200 * 138/120 = 13,200 * 23/20.
4. Compute the final value: 13,200 * 23 / 20 = 13,200 / 20 * 23 = 660 * 23 = 15,180.