How to calculate the big buy bonus?

Question

Mathematics

There is a calculator that counts from one c.u. to another at a certain rate, and if you buy right units more than a certain threshold, then a certain percentage is added to the amount (there are several such thresholds, the larger the purchase, the higher the threshold and the greater the percentage). So how can you calculate a percentage of a known purchase amount, so that this percentage can then be taken away and get the original amount of c.u.? Those. how to find the inverse formula for recalculation taking into account these percentages?
PS I'm not stupid) but I lack some knowledge)

Answer 1

The algorithm is primitive, you have to divide your trade volume into parts, equal in series to the price change limits, i.e. calculate for each limit the total volume of the exchanged currency, at each step subtract this limit from the total volume until it runs out. Then add up the amount of the received currency, and divide by your initial volume (well, or vice versa, depending on which of your currencies is the quote currency).