Answer: 63 because 21 times 3 = 63
Step-by-step explanation:
There are 63, it can't be 7 because why would there be 7 students in 21 groups, so 21 times 3 equals 63
If AP and PB are in a 1:2 ratio, it means that PB is twice AB.
So, AP must fit three times into AB, meaning that P must be at one third of the way between A and B.
