How did Americans find ideas for new technology
2 answers:
You might be interested in
assuming efficiency of each man to dig trench, in one day, for one hour is constant,
so one man, working for one hour in one day can dig 1.5 m
so 8 men, working 3 hours a day and will take, say $d$ number of days and efficiency will be constant. so,
$\frac32=\frac{220}{8\times3\times d}$
$\implies d=\frac{55}9=6.12$