From this table...plz explain to me how 50th observation is 28 and 51st is 29???

From this table...plz explain to me how 50th observation is 28 and 51st is 29??? obtained Number or students

Dear student
This is discrete frequency distribution table so it doesn't matter that 50 th observation is 28 and 51st is 29.
28 is discrete data indicating marks 28 and 29 is another discrete data indicating marks 29
regards.