I think the description of "expected value" should be clarified into "expected value of other envelope". Because if we are talking about expected value of both envelopes, there would be no paradox because the expected value of the whole game would be similar even whether you switch or not switch the envelope.

But the paradox came when we try to calculate the "expected value of other envelope", which has been calculated correctly above.

I think the description of "expected value" should be clarified into "expected value of other envelope". Because if we are talking about expected value of both envelopes, there would be no paradox because the expected value of the whole game would be similar even whether you switch or not switch the envelope.

But the paradox came when we try to calculate the "expected value of other envelope", which has been calculated correctly above.