Question

A movie earns $100 million the first week it is released. The movie earns $20 million less each additional week. Write an equation for the nth term of the arithmetic sequence.

Answer 1

an = 100 -20(n -1) . . . . . millions earned in the n-th week of release

Explanation:

The general term of an arithmetic sequence is ...

an = a1 +d(n -1)

for first term a1 and common difference d.

If we write the equation to give the sequence terms in millions, the first term is a1 = 100 and the common difference is d=-20. Putting these values in the general form, we have ...

an = 100 -20(n -1)