Question is Ambiguous. Two Answers are possible
Answer-1:
Order P: Maximum number of child(block) pointers.
So, (9+7)(P-1) + 6 <= 1024
16.P - 10 <= 1034
P = Lower bound of (1034/16)
= 64
Answer-2:
Order P: Maximum number of (value, data record pointer) pairs
So, (9+7)(P) + 6 <= 1024
16.P <= 1018
P = Lower bound of (1018/16)
= 63
PS: Order should be clear
