Question

What is the probability that at least one marble is white if a bag has 3 green and 3 white marbles four marbles are selected at the same time?

Answer 1

Hi there !
Here's the answer:

Bag contains
3 Green Balls
3 White Balls
Total Balls= 6

Let S be sample space
n(S) = no. of ways of selecting 4 marbles from 6 Balls= 6C4
= 6C2= (6×5)/2= 15

E be Event that selected ball contains at least one white ball.
( Atleast => min to max )

Possible cases:
1 white - 3C1= 3
2 white- 3C2= 6
3 white- 3C3= 1

The sum of these no. of cases is nothing but n(E)
n(E) = 3+6+1

Probability = n(E) / n(S)
= 10/15= 2/3

•°• Required probability = 2/3


:)
Hope it helps