A bag contain 12 blue, 10 Yellow, and 9 White ball what is probability that, when 2 ball are selected both are white?
1. 37/155
2. 12/137
3. 12/155
4. 155/12
A bag contain 12 blue, 10 Yellow, and 9 White ball what is probability that, when 2 ball are selected both are white?
1. 37/155
2. 12/137
3. 12/155
4. 155/12
1. 37/155
2. 12/137
3. 12/155
4. 155/12
Correct Answer – Option 3 : 12/155
Formula used:
nCr = n!/{(n-r)! × r!}
Calculation:
Let S be the sample space then,
n(S) = Number of way of selecting 2 balls out of 31 ball
⇒ 31C2 = 31!/[(31– 2)! × 2!]
⇒ (31 × 30)/2
⇒ 465
Let E be the event of getting both white balls
N(E) = 9C2 = (9 × 8)/2
⇒ 36
P(A) = n(E)/n(S)
⇒ 36/465
⇒ 12/155
∴ Probability of getting 2 white ball is 12/155