Question

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

Answer 1

Correct option is (B) 15,180

Let ‘W’ be the labour wages, and ‘T’ be the working hours. 

Now, total cost is a function of W x T 

Increase in wages = 20% 

∴ Revised wages = 1.2 W

Decrease in labour time = (100/24)%

∴ Revised time = (1 - 1/24)T = 23/24 T

∴ Revised Total cost = 1.2 x 23/24 WT = 1.15 WT

= 1.15 x 13200 = 15180