How to increase the withdrawal rate in VKCoin by increasing the number of withdrawals in another game currency?

Question

Mathematics

Hello! I need to make it so that when I withdraw my game currency in the bot in VKCoin, with an increase in the already withdrawn amount of currency and the amount of the current withdrawal amount, the rate of my currency increases.
Let's say the static rate is 7500 VKC for 1 of my currency.
If the withdrawal is 10 coins, this is 75000 VKC, but I want it to be 75000-(75000/10) VKC. It is also necessary to take into account the previous conclusions - the more it was withdrawn before, the lower the VKC rate will be.

Not necessarily the same numbers as I said, just that for every +1 coin of my currency, the rate becomes ~ 10% higher. All this is a formula, preferably.

Answer 1

K = K0*((1-DP)^(OUT/L))
K - desired rate
K0 - static rate
DP = 0.1 = 10% rate loss
OUT - how much is displayed this time
L = 1 = how many coins are needed to lose DP percent of the rate

It is also necessary to take into account the previous conclusions - the more it was withdrawn before, the lower the VKC rate will be

Multiply the formula by one more such bracket
K = K0*((1-DP)^(OUT/L))*((1-DP2)^(SUM/L2))
DP2 - rate loss due to previous withdrawals in fractions of one (1% => 0.01)
SUM - how much has already been withdrawn
L2 - how many coins had to be withdrawn to lose DP2 percent of the rate