Grisham is considering the three situations below.

I. For the first 28 days, a sunflower grows at a rate of 3.5 cm per day.

II. The value of a car depreciates at a rate of 15% per year after it is purchased.

III. The amount of bacteria in a culture triples every 2 days during an experiment.

Which of the statements describe a situation with a equal difference over an equal interval?

(1) I, only
(2) II, only
(3) I and III
(4) II and III

I don't understand what it means by "equal difference over an equal interval".

1 answer

it means that the change does not depend on the amount already present. The amount changes by a constant amount each time period. That is, a fixed amount per year, per day, etc.

So, what do you think?