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?