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Blood types A, B, O, and AB have percentages 40%, 20%, 30% and 10%. If two individuals are chosen at random, assuming independence, how do you find probability that both blood type A?

Answer 1

Grace Asher

#0.16#.

Let, #A_1# be the Event that the randomly chosen First Individual has

the Blood Group #A#, and, let, #A_2# be for the Second Individual.

#:." The Reqd. Prob.="P(A_1nnA_2)#.

But, #A_1 and A_2# are Independent Events, therefore,

# P(A_1nnA_2)=P(A_1)*P(A_2).............................................(star)#.

Since, 40% of Individuals have Blood Group A, clearly,

#P(A_1)=P(A_2)=40/100=0.4#

Hence, by #(star), "the Reqd. Prob."=0.4xx0.4=0.16#.

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Answer from HIX Tutor

When evaluating a one-sided limit, you need to be careful when a quantity is approaching zero since its sign is different depending on which way it is approaching zero from. Let us look at some examples.