I'm having trouble with an IF,AND,OR formula...

A4=08:00
B4=20:00

A10 is a time entry cell, such as 10:21
A11 is a date entry cell, such as 20/03/2005
A12 works out the day of the week according to A11 (=A11 formatted as "dddd")


I need the following: -

If the time entered in A10 is between A4 and B4 and the day of week is NOT
Saturday or Sunday the the answer should be "PEAK". If it is Saturday or
sunday, the answer should be "OFFPEAK" regardless of the time.

10:21 on 20/03/05(sun) should be OFFPEAK
10:21 on 21/03/05 (mon) should be PEAK
20:05 on 21/03/05 (mon) should be OFFPEAK

Hope I explained it well

TIA