Bunuel wrote:
64 persons can dig a trench 50 m long, 2 m wide and 2 m deep in 5 days, working 12 hours daily. In how many days, working 8 hours daily, will 80 persons dig another trench 75 m long, 4 m wide and 3 m deep?
(A) 18
(B) 27
(C) 36
(D) 45
(E) 47
64 person can dig 50*2*2 or 200m^3 in 5 days working 12 hrs daily.
So, 1 person can dig 1m^3 in \(\frac{5*64*12}{200}\) working 1 hr daily.
Therefore, 80 person can dig 75*4*3 or 900m^3 in \(\frac{5*64*12}{200}*\frac{900}{80*8}=\frac{5*12*9}{2*10}=27\)
B