The prevalence of blood types in the us population is o+: 37.4%, a+: 35.7%, b+: 8.5%, ab+: 3.4%, o–: 6.6%, a–: 6.3%, b–: 1.5%, and ab–: 0.6%. 1) a sample of 24 subjects is randomly selected from the us population. what is the probability that 8 subjects are a+. random variable x describes the number of a+ subjects among 24 selected. find ex and var x.

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step-by-step explanation:

geometry: triangles

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call the larger triangle abc

then the smaller triangle cde is similar to abc (all angles are equal, aaa).  

ab is the side that is 36, and we wish to find de, the side corresponding to ab

area_cde = area_abc - area_cde --> area_abc / area_cde = 2

let x=length of de

ratio of areas = (ratio of sides)^2

+2+=+%2836%2fx%29%5e2+

+2+=+1296%2fx%5e2+

++x%5e2+=+1296%2f2+=+648+

25.45584