21. Eighty - two percent of people using electronic cigarettes ( vapers ) are ex - smokers of conventional cigarettes . You randomly select 10 vapers . Find the probability that the first vapers who is an ex - smoker of conventional cigarettes is ( a ) the second person selected , ( b ) the fourth or fifth person selected , and ( c ) not one of the second through seventh persons selected . ( Source : Churn Mag )

answer: a

step-by-step explanation:

the answer to your question (9+10) is 19

let

step

find the slope of the line ab

we know that

the formula to calculate the slope between two points is equal to

substitute the values

step

find the equation of the line ab with the slope m and point a

we know that

the equation of the line in the slope-point form is equal to

substitute the values

convert to function form

let

therefore

the answer is the option

see the attached figure to better understand the problem