Question

How many 2 digit numbers are the product of two different primes

Answer 1

Answer:

30.

Step-by-step explanation:

2 digit Numbers which  have factor of  2:

2*3, 2*5, 2*7, 2*11, 2*13, 2*17, 2*19, 2*23, 2*29, 2*31, 2*37, 2*41, 2*43, 2*47.

That's 14.

Then there are the ones with factor 3:

3*5 ....... 3*31 = 9 numbers.

Then

5*7  to 5*19 = 5 numbers.

7*11 , 7*13 = 2 numbers.

Total is 14 + 9 + 5 + 2

=  30.

Answer 2

Answer:

From these number, only 12,15 and 21 can be represented by a product of two one-digit number