Answer: 6
Explanation:
Given : Tina is placing 30 roses and 42 tulips in vase for table decorations in her restaurant .
Each vase will hold the same number of flowers and each vase will have only one type of flower .
Then, the greatest number of flowers she can place it each vase will be the greatest common factor of 30 and 42.
Prime factorization of 30 and 42 :

We can see that greatest common factor of 30 and 42 =

Hence, the greatest number of flowers she can place it each vase =6