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,
$\frac32=\frac{220}{8\times3\times d}$
$\implies d=\frac{55}9=6.12$
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Both of them were severely hurt by nuclear radiation
Hiroshima is one of the japanese cities that was bombed by the USA with atomic bomb during ww2.
<span>Chernobyl also experience a nuclear disaster in 1986,in the USSR.
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They allowed for much stronger and more durable weapons.