How can we calculate rank of students for a specific exam? [closed]

How can we calculate rank of students for a specific exam without repetitive ranks ?

Name correct_answer negative_answer marks

ABC 20 5 60 DEF 15 8 40 GHI 16 9 40

Here we see 'ABC' get more marks his rank 1st. But 'def' and 'GHI' get same marks so their rank 2nd. But we calculate not repetitive rank for 'def' and 'GHI'. Both of them who get more correct answer it calculate rank