Question

Nick and his cousin Sara have the same birthday, but Nick is four years older than Sara. Let the variable X relresent Nick's age and Y represent Sara's age. Sketch a graph that represents the relationship between Nick's age ans Sara's age.

Answer 1

Let X represent Nick's age and Y represent Sara's age.

Then, it is given that: Nick is four years older than Sara.

We write the statement as:

`X=4+Y`

or
`Y=X-4`

The only ordered pairs (X,Y) which satisfy the equation are: (0,-4) and (4,0) as you can see in the graph also.

In the graph X axis represents the age of Nick's age and Y-axis represent the age of Sara's age and the line Y=X-4 represents the relationship between the age of both.