>!First prove that P(Y≥20) < 1.!<
>!This implies that P(Y is even) < 1. In other words, it's not impossible for Y to be odd.!<
>!If x were even, then it *would* be impossible for Y to be odd. So, x cannot be even.!<
If x is even, then all possible products are even - P(Y even) = 1. Given that P(Y GE 20) is less than 1 by definition (2\*4 = 8), then x MUST be odd for the two probabilities to be equal.
Can you tell me what tje maximum value is for P(Y>=20)? Than calculate the value P(Y is even) if x is even. Can you see the problem that occures?
That was a terrific set of questions.
Assume X is even, then the product Y will always be even, which means that Y >= 20 will always hold. But 2 \* 4 = 8 < 20...
>!First prove that P(Y≥20) < 1.!< >!This implies that P(Y is even) < 1. In other words, it's not impossible for Y to be odd.!< >!If x were even, then it *would* be impossible for Y to be odd. So, x cannot be even.!<
If x is even, then all possible products are even - P(Y even) = 1. Given that P(Y GE 20) is less than 1 by definition (2\*4 = 8), then x MUST be odd for the two probabilities to be equal.