Question

Please answer question completely, thanks?

Answer 1

As the average speed increases, the elapsed time decreases and, as the average speed decreases, the elapsed time increases, therefore, it is an inverse variation .

For inverse variations, we use the form:

`y = k/x`

where k is the constant of variation.

We are given that `y = 3" hours"` when `x = 54" mph"`

We may use this information to find the value of k:

`3" hours" = k/(54" mph")`

`k = (3" hours")(54" mph")`

`k = 162" miles"`

This makes the equation become:

`y = (162" miles")/x`

To answer the last part, we substitute `60" mph"` for `x`:

`y = (162" miles")/(60" mph")`

`y = 2.7" hours"`