Answer:
4
Step-by-step explanation:
How many selfies did Tania take? (my first answer would be too many, but that's probably not the answer you're looking for :-) )
We know that each cousin appear 2 or 3 times overall.
If she would have taken each cousin exactly 2 times, that would be 16 cousins/photos
If she would have taken each cousin exactly 3 times, that would be 24 cousins/photos
We know there's exactly 5 cousins per photo...
so we have to find a multiple of 5 cousins/photos that is between 16 and 24.
The only possibility is 20 cousins/photos. 20 / 5 = 4 photos.
