In Cisterna di Latina, there are only two brands of hamburgers available, Brand G
and Brand K. It is known that people who eat Brand G hamburger have a 40%
probability of suffering stomach pain and those who eat Brand K hamburger have a 30% probability of suffering stomach pain. Twice as many people eat Brand K
compared to Brand G hamburgers. However, no one eats both varieties. Supposing one day you meet someone suffering from stomach pain who has just eaten a hamburger, what is the probability that they have eaten Brand G and what is the probability that they have eaten Brand K?