I did Master in Pure Mathematics but I opt Physics in CE-2016.
But as a science student you know that science subjects need more time as practice needed, but in CSS 2paper per day very tiring and tough days.
You havn't time to revise properly.
But If you have firm grip on math go through you can score very well.
Pure math whole syllabus covered but Appplied math is confusing so I opt I.R for CE-2017.

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