0 votes 0 votes A bowl contains $10$ red balls and $10$ blue balls. A woman selects balls at random without looking at them. How many balls must she select to be sure of having at least three balls of the same color? How many balls must she select to be sure of having at least three blue balls? Combinatory kenneth-rosen discrete-mathematics counting pigeonhole-principle descriptive + – admin asked Apr 29, 2020 admin 3.5k views answer comment Share Follow See 1 comment See all 1 1 comment reply srestha commented Jul 11, 2020 reply Follow Share If answer is correct, plz select it 0 votes 0 votes Please log in or register to add a comment.
2 votes 2 votes FOR A Using Pigeonhole Principle we she must select X ball such that ceiling(X/2) =3 So X = 2*(3-1) +1 = 5 OR 2(red)+2(blue)+1 (either blue or red)=5 FOR B She has to select at least 13 balls to ensure the color. 10(red)+2(blue)+1(blue)=13 Mohit Kumar 6 answered Apr 29, 2020 Mohit Kumar 6 comment Share Follow See all 0 reply Please log in or register to add a comment.