Question

Out of 18 people in a room, 2 have red hair. What is the probability that a person picked at random from the room does NOT have red hair?
Give an explanation plz:)​

Answer 1

Answer :

• Total number of people in the room = 18

• Number of people with red hair = 2

• Number of people not with red hair = 18 - 2 = 16

• Probability of picking a person who doesn't have red hair = $\sf\dfrac{Number\:of\:favourable\:outcomes}{Total\:outcomes}$

Probability = 16/18

Reduce the fraction with 2

Probability = 8/9

Answer 2

Answer:

$\implies\boxed{\red{\sf P( not \ having\ red\ hair)=\dfrac{ 8}{9}}}$

Step-by-step explanation:

Given :-

• There are 18 people in the room .
• Two of them have Red hair.

And we need to find the probability that a person picked at random from the room does not have red hair . So for that firstly let us find how many people do not have red hair.

According to Question :-

$\implies n_{(red)}+ n_{(not\ red)}= 18 \\\\\implies 2 + n_{(not\ red)}= 18 \\\\\implies n_{(not\ red)}= 18 -2 =\boxed{\red{16}}$

Hence the probability is :-

$\implies P( not \ having\ red\ hair)=\dfrac{ n_{(favourable\ outcomes)}}{n_{(possible\ outcomes)}} \\\\\implies P( not \ having\ red\ hair)=\dfrac{ 16}{18} \\\\\implies\boxed{P( not \ having\ red\ hair)=\dfrac{ 8}{9}}$

Hence the required probability is 8/9 .