Hackerrank Grading Students Problem's Solution in JavaScript

HackerLand University has the following grading policy:
Every student receives a grade in the inclusive range from 0 to 100 .
Any grade less than 40 is a failing grade.
Sam is a professor at the university and likes to round each student's according to these rules:
If the difference between the grade and the next multiple of 5 is less than 3, round grade up to the next multiple of 5.
If the value of grade is less than 38, no rounding occurs as the result will still be a failing grade.
Examples
Grade =84 round to (85 - 84 is less than 3)
Grade =29 do not round (result is less than 40)
Grade =57 do not round (60 - 57 is 3 or higher)
Given the initial value of grade for each of Sam's n students, write code to automate the rounding process.

[aAmotivation-sj]

thank you SIR. It's absolutely clear after watching your video. 🙏🙏

[zakesntuli]

Wow, this is great. I need your regading changing grades

[sanafathima]

thank u sir :)
can u tell me the logic behind "extraMarks" variable 5-(value%5)??
and after writing the code can u explain the code logic ?so that we will know the logic behind it