Question

a family has 5 children. the probability of having a girl is 1/2. what is the probability of having no girls?

Answer 1

suppose you have a coin. what is the probability of it landing heads?

Answer 2

ok i know the answer to the question is .0313, anyone know how?

Answer 3

see if 1/32 is 0.0313

Answer 4

yeah how did you get 32

Answer 5

the probability of having a girl is 1/2. so the probability of having a boy is 1/2.
in a family of 5 children, all are boys. i.e, there are no girls. so the parents had five boys consecutively.
so the probability of having 5 boys in a row is 1/2 times 1/2 times 1/2 times 1/2 times 1/2

Answer 6

ok thanks, know how to get this one?
a bag contains 6 cherry, 3 orange, and 2 lemon candies. you reach in and take 3 pieces of candy at random. find the probability you with pick 2 cherry and 1 lemon

Answer 7

yes, but do you want the answer or do you want to learn how to do this?

Answer 8

learn how, i know the answer

Answer 9

okay. so suppose you have 2 candies in the bag. one is lemon and one is grape. what is the probability that you will pick the lemon candy?

Answer 10

1/2

Answer 11

okay good. suppose you have three candies. one lemon one grape and one cherry. what is the probability you pick the lemon ?

Answer 12

1/3

Answer 13

okay good. suppose you have three candies, two lemon and one cherry. what is the probability you pick a lemon candy?

Answer 14

2/3

Answer 15

okay very good.
now you have 6 cherry, 3 lemon and 2 grape candies.
what is the probability that you pick one cherry candy?

Answer 16

6/11

Answer 17

okay very good. now, you have already picked one candy. so there are ten candies left. 5 cherry, 3 lemon and 2 grape.
what is the probability that you pick a cherry candy?

Answer 18

5/10 so 1/2

Answer 19

yes, good. now there are 9 candies left. 4 cherry, 3 lemon and 2 grape. what is the probability that you pick a lemon candy?

Answer 20

3/9, and then you multiply right? thats how i tried to solve the original one but i got the wrong answer

Answer 21

yes, so the probability that you pick 2 cherry candies in a row and then one lemon candy is 6/11 times 1/2 times 1/3.

Answer 22

for 6 cherry, 3 orange, and 2 lemon; the prob of 2 cherry and 1 lemon: answer is supposed to be .1818

Answer 23

solving its that way gets .0909

Answer 24

the question says there are only 2 lemon candies and there are 3 orange candies. so for the third try, you pick a lemon candy out of 9 candies, the probability of that is 2/9
so the answer should be 6/11 times 1/2 times 2/9

Answer 25

yeah i can do that and get .0606; but the book says the answer is supposed to be .1818

Answer 26

thats why im confused

Answer 27

wait, is that supposed to be in that order?

Answer 28

it says at random

Answer 29

yeah it says random, but is the expected answer 1 cherry then 1 cherry then 1 lemon or is it that you pick three candies and you end up with 2 cherries and 1 lemon?

Answer 30

okay looks like you are not reaching in three times. you just reach in once and take three candies.

Answer 31

it says "you reach in and take 3 pieces of candy at random"

Answer 32

do you know how to figure it out that way?

Answer 33

yeah. you have to do it the following way:
6C2/11C3 times 2C1/11C3

Answer 34

c?

Answer 35

have you done permutations and combinations? BTW ignore my answer. that is incorrect. I will calculate the correct answer and post it here.

Answer 36

my teacher gave us problems to do but never taught us how, but yes we are supposed to be doing permutations and combinations. any quick formulas i can jot down for the test?

Answer 37

The answer is 6C2 times 2C1 divided by 11C3

Answer 38

ohh ok that makes sense! thanks!

Answer 39

so that is 15 times 2 divided by 165 = 30/165 = 0.181818181

Answer 40

you dont know how to do combinations?

Answer 41

nope:(

Answer 42

then how did it make sense to you?

Answer 43

she showed us the calculator commands for the c but didnt show us what it was for, now i know

Answer 44

http://www.mathsisfun.com/combinatorics/combinations-permutations.html

Answer 45

read through that and ask me if you have doubts.

Answer 46

thanks soo much!

Answer 47

probability in poker, a flush in any suit?

Answer 48

what is your question?