Key points

• CSAT (GS Paper II) is qualifying: you need at least 33%, i.e. 66 out of 200.
• 80 questions, 2.5 marks each; a wrong answer costs 1/3 of the question's marks (0.83).
• Sections: reading comprehension, logical reasoning, analytical ability, basic numeracy and data interpretation.
• Percentage change = (new − old) / old × 100. Successive changes of a% and b% = a + b + ab/100.
• Speed = distance / time; average speed for equal distances at x and y = 2xy / (x + y).