Example of Inverse Proportionality

When we have in one ratio that one quantity increases or increases and the other decreases in a similar proportion, we say that it is an inverse proportionality. Let's look at an example related to this concept in order to clarify the issue.

1) Example of inverse proportionality

Suppose that on a farm 200 ducks consume all the food that we have stored in a warehouse within 15 days. How long will it take 300 ducks to finish with a similar amount of stored feed?
To solve this example of inverse proportionality we must carry out the following reasoning:
200 ducks 15 days

300 ducks x days
As it is an inverse proportionality, the operation to be carried out is: 15 x 200
= 10
300 
So we come to the conclusion that 300 ducks will finish the same amount of feed in 10 days.

2) Example of inverse proportionality

Students from a school in Mexico hire a bus in order to take a beautiful end-of-year tour. In the case that a total of 32 students travel to complete the total cost of the trip, each of them will have to pay the sum of $ 400. The question is, if only 25 students travel, how much money should each of them pay?

We must consider that if fewer students travel then the price for each student will increase, since they will not have to raise the total money to pay for the bus to be hired.
So we know that: 32 students (will pay) $ 400 each
25 students (will pay) ...
The operation to be carried out is as follows: 32 x 400
= 512
25 
The answer is that if only 25 students travel, they will each have to pay $ 512.

3) Example of inverse proportionality

To build a wall in a house, a team of 6 workers has been formed. Completing this task took a total of 4 hours. How many more workers would it have taken to do a similar job in a total of 3 hours?
We have a total of 6 workers do the task in 4 hours
3 hours do the homework a total of ...
Reasoning the same as the previous examples: 4 x 6
= 8
3
The solution to the example is 8 workers.

Keep reading: Direct proportionality.