'How much marks did you get' is grammatically correct or not?

Answer 1

No, because "much" is used to refer to something that's singular. That means that it is more than one of something- in this case, marks is plural. To tell, you can look at what "much" is referring to and ask if it would work in the blank space in "_____ is" (singular) or the blank space in " _____ are" (plural). In this case, it works with "marks are".

If you wanted to correct that sentence, then you could say, "How many marks did you get?" (If you are talking about the British use of "marks" as the grade or number of points you got on a school assignment, then you would have to change the whole sentence. For example, you could use "How good were your marks on the test?" or something like that.)