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

The total of 1+4+3 marbles is 8 marbles

P( blue ) = blue /total = 4/8 = 1/2

He replaces it, so there are still 8 marbles in the bag

P(blue 2nd draw) = blue /total = 4/8 = 1/2

P(blue,replace, blue) = 1/2*1/2 = 1/4

Answer 2

1/4

Explanation:

There is a total of 1+4+3 marbles = 8 marbles

P( blue ) = blue /total = 4/8 = 1/2

He replaces it

There are still 8 marbles in the bag

P(blue 2nd draw) = blue /total = 4/8 = 1/2

P(blue,replace, blue) = 1/2*1/2 = 1/4