X² =64
x = √64
x = 8
answer is 8
8² = 64
7-4=3
........................
Let the full marks be represented by = x
As given, 80% of x is 75
So,

x= 
x=93.75
Hence, full marks is 93.75
We can check also-
=75
Answer:
Ismail
Step-by-step explanation:
because he did 2/3