Question

Balls numbered $1$ through $20$ are placed in a bag. Three balls are drawn out of the bag without replacement. What is the probability that all the balls have odd numbers on them?

• A. $0.155$
• B. $0.105$
• C. $0.225$
• D. None of these

Answer 1

Answer: (B)

$0.105$

There are 20 balls in a bag.

Odd numbers between 1-20 are {1, 3, 5, 7, 9, 11, 13, 15, 17, 19}=10

The probability of getting 3 odd numbered balls without replacement:

$=\frac{10}{20}\times \frac{9}{19}\times \frac{8}{18}=\frac{720}{6840}=0.105$