Answer: Hence, the correct size of boys group is 5 and girls is 6.
Explanation:
Since we have given that
Number of boys = 60
Number of girls = 72
We need to divide the students into gender specific groups of the largest possible size.
For this we will find "HCF of 60 and 72" which is equal to "12".
So, the correct size of each group is 12 in which number of boys would be

Number of girls would be

Hence, the correct size of boys group is 5 and girls is 6.