Page 8 - Mathematics Literacy Grade 11

Unit 3: Inverse relationship

The third type of relationship is where there is an inverse relationship between two
variables such that when one increases, the other decreases, but the product of the
values always remains the same.

Example: an increase in the number of builders decreases the number of hours it
will take to build a house. When sharing an amount of money equally, the more
people the fewer amounts each will get.

The graph bellow is an example of an inverse relationship. Medication is used in
the treatment of HIV in order to slow down the progression of the disease. These
medications are referred to as "anti-retroviral" (ARVs). When taken correctly ARVs
can reduce the viral load in the blood. The viral load measures the amount of virus
in the blood. The graph shows us that the longer someone is on ARVs the lower
the viral load of that person.

Exercise 1

1. Mickey pays R599 per month to watch DSTV channels. The table below
shows how many hours Mickey watched television for five months and how
much he had to pay every month:

1.1 Write down the dependent and independent variables.

1.2 Describe how the two variables change in each row. Do they display any
patterns?

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