what percent of the two digit whole numbers are primes ?1.21 2.23 3.25 4.29? explain the ans
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To determine the percentage of two-digit whole numbers that are primes, we need to find the total number of two-digit whole numbers and then count how many of them are primes.
First, let's find the total number of two-digit whole numbers. A two-digit number consists of two digits, one in the tens place and one in the units place. The range of options for the tens place is from 1 to 9 because it cannot be zero, and for the units place, it can be any digit from 0 to 9. Therefore, the total number of two-digit whole numbers is 9 (options for tens place) multiplied by 10 (options for units place), which equals 90.
Now let's determine how many of these two-digit whole numbers are prime. To check if a number is prime, we need to divide it only by the numbers from 2 to the square root of the number itself. If any of these divisions result in a whole number, the number is not prime.
The prime numbers between 10 and 99 are: 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, and 97. Counting these numbers, we find that there are 21 two-digit prime numbers.
To calculate the percentage of two-digit whole numbers that are primes, we divide the number of two-digit prime numbers (21) by the total number of two-digit whole numbers (90) and multiply by 100.
(21/90) * 100 = 23.33%
So, the answer is that approximately 23.33% of the two-digit whole numbers are primes.