Why manday work by measurement rate need?

When we take a job on item rate, we have to deploy laborer to do that job. The laborer charges some money per day to do that job, so how much work should we take so that we do not incur any loss. The “manday work by measurement rate” calculator calculates the minimum work as per the labor charge.

What is the manday work by measurement rate formula?

a= piece rate of work per unit
b= average worker rate for manday
b= (skilled rate + unskilled rate)/2
c= contractor profit in %
d= total worker engaged for one manday
e= total time in mandays worker engaged
manday work or production rate in unit , w
manday work = work done in a 8 hour
work done in one manday, x unit
work done in total time, z unit
Suppose worker work w unit in a manday
work done in money = worker and contractor charge
w*a = b + b*c/100
w = (b + b*c*0.01)/a unit/manday
x = w*d unit
y = x*e unit