Question 1075683
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There are 50 numbers from 1 to 50 inclusively.


Half of them, 25, are odd.  All primes (except of 2) are among odd numbers.


There is only one prime which is even: it is 2.


So, 25 + 1 = 26 numbers of 50 are  EITHER  an odd  OR  a prime.


The rest 24 = 50 - 26 are  NEITHER  an odd  NOR  a prime.


Thus your answer regarding the probability is {{{24/50}}} = {{{12/25}}} = 0.48.
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