Question

Below two situations are described in words. In each case, decide

Answer 1

(a)

If by "age in years" you mean that you only consider whole years, then this is not a one-to-one function, because you will have the same output for 365 inputs:

• If you're 0 to 364 days old, your age in years is 0
• If you're 365 to 729 days old, your age in years is 1
• ....

So, you can see that it is not true that every different input yields a different output.

(b)

This is a one-to-one function: since one mile is 1.609 kilometers, you can convert miles per hour into kilometers per hour by multiplying by 1.609:

x mph = 1.609x km/h

The inverse function would be

x km/h = x/1.609 mph.