Answer:
72
Explanation:
We are assuming that all girls in the group bought the same number of items.
Therefore, we need to find the highest common factor of 72, 144 and 216.
HCF
72 = 2 * 2 * 2 * 3 * 3
144 = 2 * 2 * 2 * 2 * 3 * 3
216 = 2 * 2 * 2 * 3 * 3 * 3
The product of the emboldened numbers is the highest common factor.
That is:
2 * 2 * 2 * 3 * 3 = 72
Therefore, the largest possible number of girls in the group is 72.