Calculating returns of bid using R

Dear R Users,

I am practicing problems in the field of finance and economics. While
searching, I got problem like this. And I want to solve the following
problem using R. I dont have any clue how to incorporate this in R. Please
help me!!

Question:

A chit fund has 25 members. Each month they contribute Rs 2000 each. End of
the month, the person who bids the lowest for the corpus, gets his bid. The
group organizer gets paid a fixed commission of Rs 2500 each month (5% of
25*2000).It is deducted from the bid winner's corpus. The remaining amount
is distributed among all the 25 customers equally.
Based on the above details calculate using R

1. What is the Annualized  Return of the person who bids in the last month
?
2. What is the Annualized Return of the person who bids in the first month ?
3. Write an R script which calculates the annualized return of chit fund
participant ?- Show the Return % for each month's bid winner.

Herewith attached the excel file for calculation.

Thanks
Sripriya