Question 1142523
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First,  I checked that the sum of all numbers in the Table is  200 :    38 + 82 + 24 + 56 = 200.      ! Correct !



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(a)  P = {{{(24+56)/200}}} = {{{80/200}}} = {{{40/100}}} = {{{2/5}}} = 0.4 = 40%.



(b)  P = {{{((24+56) + 38)/200}}} = {{{118/200}}} = {{{59/100}}} = 0.59 = 59%.


         To the total number of female teens add the number of smoking male teens;  then relate the sum to 200.


         Very simple and does not require additional explanations.



(c)  P = {{{38/(38+82)}}} = {{{38/80}}} = {{{19/40}}} = 0.475 = 47.5%.


     It looks OBVIOUS to me, since in this case you, actually, select among 80 male teens.
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All questions are answered.