209k views
1 vote
Forty percent of the first 20 whole numbers are prime. How many of the first 20 whole numbers are prime?

User Konqi
by
7.8k points

2 Answers

2 votes

Answer:

8!!!

Explanation:

YW

User Carrie Hall
by
8.8k points
2 votes

Answer:

The primes are 2, 3, 5, 7, 11, 13, 17, 19. There are 8 of them, so they make up 40% of the numbers 1–20.

Explanation:

We are given to find the percentage of the first 20 natural numbers that are prime.

We know that the first 20 natural numbers are 1, 2, 3, 4, . . . , 19, 20.

And, the prime numbers among them are 2, 3, 5, 7, 11, 13, 17 and 19.

So, if S be the sample space for the experiment and A be the event of selecting a prime number.

Then, we have n(S) = 20 and n(A) = 8.

Therefore, the probability of event A is given by

P(A) = n(A) / n(S) = 8/20 = 2/5 x 100% = 40%

Thus, the required percentage is 40%.

User Bowdzone
by
7.4k points

No related questions found

Welcome to QAmmunity.org, where you can ask questions and receive answers from other members of our community.

9.4m questions

12.2m answers

Categories