22270d
1) Since the sales have been modeled by this recursive formula, we need to make reference to the prior item in the sequence to find the next one:
a) P_1 and P_2

Note that whenever we have a recursive formula we'll need the prior item to get the subsequent one.
b) Explicit formula for P_N
When we have an explicit formula, we don't need the prior term. So let's find an explicit one:

Note that the difference between P_2 and P_1 is 12,000.
c) Now, let's pick this explicit formula and find P_10:

d) Let's use the explicit formula to find when, in years the store is going to exceed 97000
97000=27000+12