How many positive integers e less than 30 have no common prime factor with 30?
Select.
A) 5 B) 6 C) 7 D) 8 E) 9
e=30=2*3*5. So, the number must be less than 30 and not have primes 2, 3, or 5.   This means that the number could be: 1, 7, 11, 13, 17, 19, 23, or 29. Total of 8 numbers.   Answer: 8.
<result>D</result>
How many positive integers e less than 30 have no common prime factor with 30?