How to make a calculator in the product card?

Question

Electronic commerce

Good day, dear forum users, tell me how you can make a calculator like on mtort.ru or you can see it in the attached screenshot.
The logic of the calculator is as follows:
If the user selects 2 kg of cake, then 10 people are displayed, if he selects 2.5 kg of cake, then 13 people are displayed, if he selects 3 kg of cake, then 15 people are displayed, etc.
Also, the Calculator should work in reverse logic, i.e.:
If a person chooses 15 people, then 3 kg of cake is displayed, if 13 people, then 2.5 kg is displayed.
Please tell me if there are any plugins or solutions ready for this