Question

. Which represents the type of sequence: -99, -96, -92, -87, -81, …? a. both arithmetic and geometric b. neither arithmetic nor geometric c. geometric d. arithmetic 2. A town has a population of 32,000 in the year 2002; 35,200 in the year 2003; 38,720 in the year 2004; and 42,592 in the year 2005. If this pattern continues, what will the population be in the year 2016? a. 100,430 b. 110,473 c. 121,520 d. 133,672

Answer 1

1. B. Neither arithmetic nor geometric.
Solving for the common difference of each pairs of adjacent numbers, you can see that the differences are not the same, so it is not arithmetic.
If you divide the a number by its previous adjacent number, then the common ratios are still not the same, so it is not geometric as well.

2. C. 121,520
The populations are geometric sequence with 11/10 as its common ratio. We use the formula for finding the nth term of a geometric sequence. Keep in mind that we are looking for the 15th term.