Question 1157292
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<pre>

Shortly speaking, the entire job, measured in working men-days, is the same in both cases.


It gives you an equation


    6*10 = 15*d


for the unknown number of days "d".


From the equation,  d = {{{(6*10)/15}}} = {{{60/15}}} = 4.


<U>ANSWER</U>.  4 days.
</pre>

Solved.