a.

Find an exponential function to model the percent of impurity left after the kerosene travels x feet.

of the impurities are removed for every foot.

Since of the impurities are removed for every foot remaining impurities .

The percent of impurity left after the kerosene travels x feet  is .

b.

The function .

Graph of the function .

c.

Find percent of the impurity remains after the kerosene travels  feet.

Substitute in .

.

Percent of the impurity remains after the kerosene travels  feet is .

d.

No, because the graph has a horizontal asymptote , so the percentage of impurities never reach to .

a.

The percent of impurity left after the kerosene travels x feet  is .

b.

Graph of the function is :

c.

Percent of the impurity remains after the kerosene travels  feet is .

d.

The percentage of impurities never reach to .