The time required to complete a job varies inversely as the number of people working. it took 4 hours for 7 electricians to wire a building. how long would it have taken 3 electricians to have done the job?

Let's assign variables

The time required to wire a building: y

The number of electricians to have done this job: x


y varies inversely as x

so that:

where  k is the proportional constant

To calculate the value of k, plug in the values of x and y:
x=7
y=4



Now, write down the relation between x and y:


"how long would it have taken 3 electricians to have done the job?"
x=3
Let's find out y:


So it would take 9 hours and 20 minutes to have this job done.

M< 5 = 80 , < 2 = 80, < 6= 100, < 3= 100, < 7= 80, < 4= 80, < 8= 100