Question

A bag has 1 red marble, 4 blue marbles, and 3 green marbles. Peter draws a marble randomly from the bag, replaces it, and then draws another marble randomly. What is the probability of drawing 2 blue marbles in a row? Explain your answer.

Answer 1

@phi could you help?

Answer 2

the chance of picking a blue marble is the fraction # of blue marbles / total # of marble.s

how many blue marbles do you have ?
how many total?

Answer 3

there are 4 blue marbles and 8 marbles in all

Answer 4

so the chance of picking a blue marble is that fraction. what is it ?

Answer 5

4/8...?

Answer 6

yes. and you can simplify that to what ?

Answer 7

1/2

Answer 8

now we are ready to do the problem:
the chance of picking a blue marble is ½
we then put the marble back in the bag (if we did not , the chances change because we would have fewer blue marbles and a different total)

next, we pick again. the chance of getting a blue marble is ½

the chance of getting 2 blue in 2 picks is found by *mulitplying* the probabilities

Answer 9

ok..what are ht probabilities?

Answer 10

the*

Answer 11

½ and ½

Answer 12

oh ok...thats 1/4 right?

Answer 13

yes, you multiply top times top: 1*1
and bottom times bottom: 2*2
you get ¼

Answer 14

so that the answer 1/4?

Answer 15

yes

Answer 16

ok thx so much!