Call a number prime-looking if it is composite but not divisible by 2, 3, or 5. How many prime-looking numbers are there less than 100?
I'm assuming that by prime-looking you mean any number that is NOT divisible by ALL three numbers [2, 3 and 5]. If that is correct, I can only think of 3 such numbers:
The numbers are: 49, 77 and 91