Go through the below-provided link to check answer key of JEE Main 2018:-

Link for all sets question paper and answer key:- https://engineering.careers360.com/articles/jee-main-answer-key

The correct responses in the answer key have to be compared to the response sheet of yours.

You need to follow the official marking scheme to calculate the probable scores of JEE Main 2018.

Correct answer:- +4 marks

Wrong answer:- -1 mark

If you have calculated your JEE Main scores, head over to Carers360 rank predict to predict your ranks.

Link to the page:- https://engineering.careers360.com/-articles/jee-main-rank-predictor

( However, the candidates will have to remember that the data is indicative in nature. )

All the very best and good luck.