The time t required to do a job varies inversely as the number of people working. It takes 4 hr for cooks to prepare the food a wedding rehearsal dinner. How long will it take 8 cooks to prepare the dinner?
Solution:-
This in inverse variation. The time to prepare the food decreases as the number of cooks increases.
Since the time to prepare t varies inversely as the number of cooks P, use the form t(P) = 
.
To find the variation constant, substitute 6 for P and 4 for t(6), then solve for k.
4 = 
Solve for k.
K = 24
Write the equation of variation.
t(P) = 
Now, use the equation of variation to find time it takes 8 cooks to prepare the dinner.
t(p ) = 
= 3
It takes 8 cooks 3 hr to prepare the dinner.