A roulette wheel is divided into 25 sectors of equal area numbered from 1 to 25. let X be the number that occurs when
the wheel is span. Find : (i) Probability mass function of X,
(ii).P (X 25), (iii) Mean of X, (iv) Standard deviation of X.​

1. If it is intersection then it SHOULD be included in both the sets right? Now we know that odd numbers from 1-100 but the second set are multiples of 5 from 50-150! So we mainly need to look for common numbers which are ODD and are a MULTIPLE OF 5 BETWEEN 50 - 100!! So A={51,53,57,59,6199} B={55,60,65,7095} [We stop till 100 because set A has no such element] So what is A ∩ B here? A ∩ B = {All odd numbers and multiples of 5 between 50 - 100}