If Mustafa scored 75 instead of 57 for maths his average of four subjects would have been 60. What is his total mark.
Let us consider the situation where Mustafa has scored average 60 with 75 marks for math.
So total marks for four subjects `= 60xx4 = 240`
We know he got 75 for math.
So marks of other 3 subjects `= 240-75 = 165`
so even he scored 57 marks he has 165 for the other 3 subjects. So the actual mark of Mustafa is `(165+57) = 222`
So total mark of Mustafa is 222 marks.