Help in a fomula
 

can you help me out in below mentioned
i need fomula which calculate Amount in PKR automatically.

A B C D
E
unit rcvd todal days Till to date free days no of units amount in pkr
5-nov-08 67 5 1 25800

i need the formula condition of if which will work like this
total number of days 65
free days 5
rest days 60
now in a column e we need result pkr 258000 automatically which will work
like
1st 5 days = pkr 80 next 5 days = pkr 160 after 10 days fix amount pkr=320

above charges are p/day charges

example
1st 5 days which will start from 10-nov-2008 = 80 x (total number of
units) x pkr 80
next 5 days which will start from 15-nov-2008= 160 x (total number of
units) x pkr160
after this if days left it can multiply with pkr 320 till end

result
amount (total units) upto 14-nov = 6000 pkr
amount ( c4 ) upto 19-nov=12000 pkr
amount ( c4 ) upto today/08-nov = 240000 pkr

total 258000

Regards
Malik Nadeem