A very general solution, which works regardless of how the numbers in the envelope are picked: Choose a monotonically increasing function f with values between

A very general solution, which works regardless of how the numbers in the envelope are picked: Choose a monotonically increasing function f with values between 0 and 1. Choose one of the envelopes at random. Then look at the number x in the envelope. Then, with probability f(x) say that you have the larger envelope.