how many positive integers less than 30 have no common prime factor with 30 ?
"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 : d ."
divide(factorial(subtract(add(const_4, 30), const_1)), multiply(factorial(30), factorial(subtract(const_4, const_1))))