1.Suppose you pay $16,000 for a new car and estimate that it will be worth 20% less with each passing year. What will your car be worth after 3 years?

Question

2.A school club uses a telephone chain to inform members of changes in plans. The club president calls 2 members, each of whom calls 2 members, and so on. The process must be repeated 5 times. How many members are in the club?
For 1. i got about 10,000 and 2. i got 32 members

Answer 1

16,000 (.8)^3 = 8192

2^5 = 32

Answer 2

2.
Use the formula for partial sums Sn=a1(1-r^n)/1-2.

a1 is 1 because it started off as one person.
r is 2 (rate of people calling)
n is 6 because the process is repeated 5 times (plus the first call)
so s6=1(1-2^6)/1-2
s6=63.