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… · ABC26GN3356

Let the required number of days be $x$. More persons, Less days (Indirect Proportion). More length, More days (Direct Proportion). More width, More days (Direct Proportion). More depth, More days (Direct Proportion). Less working hrs, More days (Indirect Proportion). Persons $80:64$, Length $50:75$, Width $2:4$, Depth $2:3$, Working hrs $8:12$ :: $5:x$. $\therefore 80 \times 50 \times 2 \times 2 \times 8 \times x = 64 \times 75 \times 4 \times 3 \times 12 \times 5 \Leftrightarrow x = \frac{64 \times 75 \times 4 \times 3 \times 12 \times 5}{80 \times 50 \times 2 \times 2 \times 8} = 27$.