Explain why the gcf of two numbers is sometimes 1

The number 1 is common factor between any set of numbers, but, sometimes is the only common factor.

Step-by-step explanation:

This happens when the numbers do not have common prime factors, like 5 and 7.

Since 1 is a prime number, you can consider it the common primer factor of every set of numbers.

Remember:

If 'a' is a number, a prime factor of it would be 1, since a*1=a

the ratio of balloons to tables is 5: 2 and the constant variation is 5.

the equation is y=5x