Hello 

To crack CAT Exam its very essential to clear the Basic concepts in Mathematics. You must have good command over mathematics for this you must practice more and more no. of Questions. You can take help from the Model Question papers and Books for clearing this section. 

Hello Abhijit, 

Well it is true that the Quantitative Aptitute section is quite tough in the CAT but the link attached below will help you with some tips how to prepare for this section.

https://www.google.com/url?sa=i&source=web&cd=&ved=2ahUKEwj89pHW5N_fAhUB148KHYy5ABUQzPwBegQIARAC&url=https%3A%2F%2Fbschool.careers360.com%2Farticles%2Fhow-prepare-for-cat-quantitative-ability&psig=AOvVaw2WuTKLYF8v_wT_9b5TYE6w&ust=1547091924745964