The <em>correct answer</em> is:
12 bouquets, each having 6 red roses, 5 pink roses, and 4 yellow roses.
Explanation:
To find the number of bouquets we can make, we find the GCF (greatest common factor) of the three numbers, 72, 60 and 48. To do this, we find the prime factorization of each:

We look for factors that all 3 numbers have in common. These factors are 2, 2 and 3; 2(2)(3)=12, so we can make 12 bouquets.
72/12 = 6; this means we use 6 red roses in each bouquet.
60/12 = 5; this means we use 5 pink roses in each bouquet.
48/12 = 4; this means we use 4 yellow roses in each bouquet.