Which is the best book or resource for CAT Linear Equations?

Candidates can study Coordinate Geometry from How to Prepare for Quantitative Aptitude for CAT by Arun Sharma. Quantitative Aptitude for CAT by Nishit K. Sinha is another helpful resource. 

Yes. Coordinate Geometry is a useful topic in CAT Quant, especially for solving questions involving graphs, equations of lines, distances, slopes and geometric properties.

There is no fixed number of questions from Coordinate Geometry in CAT. Usually, one question may appear directly or indirectly through different topics.

Yes. Linear Equations is an important topic for CAT Quant. Its concepts are used in questions based on ratios, mixtures, ages, time and work, profit and loss, etc.

CAT does not follow a fixed number of questions for Linear Equations. One or more questions may involve linear equations directly or as Algebra, Arithmetic or word problems.