Question

D) A bag contains 6 black and 4 white marbles. A marble is drawn at random from

the bag and it is replaced to draw another marble. By using a tree diagram, find the
probability of getting
(i) both of them of the same colour.
(ii) Both of them of the different colours.
Please help!​

Answer 1

Answer: (i) 13/25 = 52% (i) 12/25 = 48%

Explanation:

Notes:

• "and" means multiply
• "or" means add

(i) If they are both the same color, then you draw a

Black Marble and Black Marble or White Marble and White Marble

(6 black/10 total) x (6 black/10 total) + (4 white/10 total) x (4 white/10 total)

= 36/100 + 16/100

= 52/100 (52%)

= 13/25

(ii) If they are different colors, then you draw a

Black Marble and White Marble or White Marble and Black Marble

(6 black/10 total) x (4 black/10 total) + (4 white/10 total) x (5 white/10 total)

= 24/100 + 24/100

= 48/100 (48%)

= 12/25

see Tree Diagram below