Question

Question #f8ee7

Answer 1

In this case the total cost is directly proportional to the number of photos developed.

Explanation:

The cost of each photo developed `C` is constant over the full range of the number of photos developed `ND`.

So total the cost `TC` increases directly as the number of photos developed is increased.

`TC = C xx ND`

If you buy only one photo:

`TC = $0.25 xx 1 = $0.25`

If you buy 10 photos:

`TC = $0.25 xx 10 = $2.50`

The total cost `TC` is increasing as the number of photos developed `ND` increases (multiplied by a constant multiplier `C`).

Then `TC` is directly proportional the number of photos developed `ND`.