Answer:
21, 22 and 26
Step-by-step explanation:
To answer this question first we need to know which are the factors of 12:
So, now, we need 3 numbers that are <u>between 20 and 30 and that only have one common factor with 12</u>, in other words, they need to have just a 2 or a 3 in their factorization.
Let's take number 21:
, we can see that 21 only has a 3 and a prime so therefore it has only one common factor with 12
Now, let's take the number 22,
, thus since 22 has a 2 and a prime, it has only one common factor with 12.
Now, let's take the number 26
, thus, since 26 has a 2 and a prime, it has only one common factor with 12.
Thus, the three possible answers are 21, 22 and 26