Which positive integer less than 21 are relatively prime to 21?
A. 18
B. 19
C. 21
D. 24
Answer:A
Which positive integer less than 21 are relatively prime to 21?
A. 18 B. 19 C. 21 D. 24
Explanation: gcd(19,21) = 1. According to the definition of relatively prime gcd of two numbers is 1.