It takes 1 person 100 days to paint a house.
With 2 persons, we will need 100÷2 days.
With 3 persons, we will need 100÷3 days.
Let the number of persons be x and the number of days be y
By tabulating the above scenario, we will get:
Now, to plot the points, we'll get:
[Notice that while the values decrease, the points do not fall on a straight line?]
[In other words, the decrease does not follow equal 'steps' like what we see in the linear graph]
By joining the dots, we get a reciprocal graph with the equation:
A standard reciprocal graph will look like this (appears in both 1st and 3rd quadrant):
If we study the relationship carefully, this is an inverse relationship:
Since 100 is a constant value, we represent 100 by k . Hence, the above can be rewritten as: