I am having less time.Is arihant 40 days JEE Mains book enough ??

I dont think you will be able to crack jee mains,by studying one book,If you donot have sound knowledge then it would be difficul to crack.So I believe that,you should have gone through standard books of all the subjects.If you have completed the standard books,then you can use it as a reference source.It will be helpful in revision.
If you have less time then i believe you should go for NCERT+the arihant book.
Then it would be good.If you face problem in studying concept then search in reference book of the particular subject