£25 in a purse and shared among 4 friends for drinks. Shared among three then yourself and then friend 4. That makes 5.
Give your first friend £1 plus 1 / 6 of the money remaining.
Give your second friend £2 plus 1 / 6 of the money remaining.
Give her third friend £3 plus 16 of the money remaining, and yourself £4 and 1 /6 of the remaining and give your 5th friend £5 and 1/6 of the remaining. We know it cna be shared as there are less than 6 people and always a balance. I cannot work out who gets more money yourself or friend 1,2,3,4 from the £25