Hello aspirant,

Hope you are doing absolutely great.

So with regard to your query, the best books for the purpose english subject for any competitive exam is "Objective General English" by Arihant Publications. And for the purpose of Quantitative Aptitude, that is basic maths, S. Chand Publications' R.S. Agarwals' Quantitative Aptitude is the best one. These two will definitely help you to clear the competitive exams.

Hope this helps you!!