a) what is the probablity that every one selected is right handed.
b) If sarah and mike, 2 left handers, have already been chosen, what is the probablity that all other members selected will be right handed?
2007-01-07 16:04:35 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Mathematics
a) what is the probablity that every one selected is right handed.
(11C7) / (15C7) = 22/91 ≈ 0.2417582
b) If sarah and mike, 2 left handers, have already been chosen, what is the probablity that all other members selected will be right handed?
(11C5) / (13C5) = 14/39 ≈ 0.3589743
2007-01-07 16:49:28 · answer #1 · answered by Northstar 7 · 0⤊ 0⤋
a. when the first of the 7 is selected the chance of being right handed is 11/15. the next is 10/14, and so on. just multiply down to 5/9.
b. so that leaves 13 people, 11 right handed. start with 11/13 and work down accordingly.
2007-01-08 11:14:30 · answer #2 · answered by SAH 2 · 0⤊ 0⤋
a. C(4, 0) x C(11, 7) / C(15, 7)
b. C(2, 0) x C(11, 5) / C(13 , 5) ???? I'm not sure about this one. It's too late to think clearly.
2007-01-07 16:18:22 · answer #3 · answered by JM 4 · 0⤊ 0⤋