The series is an arithmetic series.
The progression has a common difference of 1. You can tell because it involves a plus sign, which is indicative of an arithmetic progression,
A geometric progression would include multiplying the numbers by a certain amount. For example:
1, 3, 9, 27 ... 243
In this series, you multiply the numbers by three to get your answer.<span />
The answer would be
C = 10
P = 20
So then what is the problem u need help with? I'd be happy to help.
Answer:
29 and 31 are the only primes.