CDS (II) 2020 · Elementary Mathematics
A full Elementary Mathematics paper in the UPSC CDS pattern: 100 questions in 2 hours, with a third of the question's marks deducted for every wrong answer. Arithmetic, algebra, trigonometry, geometry, mensuration and statistics at Class 10 level, against the clock.
100questions
100marks
2 hoursno calculator
31/51/18easy / medium / hard
Topics in this paper
Mathematics · 100 questions
- Number system6
- Time, speed and distance6
- Simple and compound interest4
- Heights and distances4
- Trigonometric identities4
- Mean4
- Percentage3
- Profit and loss3
- Ratio and proportion3
- Time and work3
- Quadratic equations3
- Surds3
- HCF and LCM2
- Averages2
Sample question from this paper
HCF and LCM · medium
Three traffic lights change after every 48 s, 72 s and 108 s respectively. If they change together at 8:00:00 a.m., they will next change together at
- A. 8:06:00 a.m.
- B. 8:07:48 a.m.
- C. 8:07:12 a.m.
- D. 8:12:00 a.m.
Show answer and solution
Answer: C
The lights coincide after seconds. , , , so LCM s min s. The trap is adding 432 s as 4 min 32 s or choosing a multiple of 60 s.
The lights coincide after seconds. , , , so LCM s min s. The trap is adding 432 s as 4 min 32 s or choosing a multiple of 60 s.