Hi.

It means that out of 100 marks you should have atleast 50 marks each in Physics as well as in Maths.

Suppose, if you have 45/100 in maths and 60/100 in physics then your total is 105/200 which is more than 50% of total marks but you will not be considered for registration because you less less than 50 marks in maths.

Incase you have a further specific query, please feel free to comment.

Best of Luck