First slide

Theorems of probability

Question

Three numbers are chosen at random from the first 20 natural numbers. Then the probability that their product is odd is

Easy

A

$\frac{^{10} C_{3}}{^{20} C_{3}}$
B

$1 - \frac{^{10} C_{3}}{^{20} C_{3}}$
C

$\frac{{(^{10} C_{1})}^{3}}{^{20} C_{3}}$
D

$\frac{^{10} C_{1}}{^{20} C_{3}}$

Solution

$n (S) = 20_{C_{3}}$
If the product is odd then all the 3 numbers are odd

$n (E) = 10_{C_{3}}$

$P (E) = \frac{^{10}_{C_{3}}}{^{20}_{C_{3}}}$

$∴$ The probability that their product is odd is $\frac{^{10} C_{3}}{^{20} C_{3}}$

Get Instant Solutions

When in doubt download our app. Now available Google Play Store- Doubts App

Recieve an sms with download link

Doubts App

OR

SCAN ME

Doubts App

Doubts App