The more the workers, the lesser time it takes to complete the work
Therefore number of workers is inversely proportional to time.
Let
w= number of workers and
t= time
w∝Remove the proportionality by introducing equal to and a constant
Let
k= contant
w=k×w=Since we know the number of workers and time taken, we can calculate for the value of
kw=15t=1215=Multiply both sides by 12 to get rid of the denominator.
15×12=kThe general equation is therefore
w=Now we are given the number of workers to find time.
Number of workers
(w)=99=Multiply both sides by
t to get rid of the denominator
9×t=15×12Solve for the value of
t by dividing both sides by 9
t=t=5×4=20Note: 3 divides 12, 4 times and 9, 3 times. 3 divides itself once and 15, 5 times Time taken for the 9 boys is 20 hours.