Question 844182
Uniform rates problem, and here, you first want to find the rate for one man.  The rates of men working together are simply added.


If 8 men need 1 day to do the job of "prepare one book", then 1 man needs 8 times longer than 8 men.  


The way you can show the uniform rate equation can be {{{R*t=j}}}, the variables being Rate, time, job.  Units need to be consistent.  If r is the rate for 1 man, and n is the number of men working simultaneously, then you can write, {{{(nr)t=j}}}.


Your example can take the process of (1) Find the one-man rate;  (2)  Setup the uniform rate equation according to {{{n*rt=j}}} and solve for n.