In this article we will see some CDSE  important math questions from previous years CDSE papers.
UPSC CDS 1 2017Â Math Important Questions
1. If x = 4, y = 12 and x α y, then
a. 4y = 3x
b. x = 3y
c. y = 3x
d. 4x = 3y
2. The missing number in the series 5, 13, 9, 17, 13, 21, ……… is
a. 29
b. 25
c. 13
d. 17
3.The compound interest for two years on a capital is Rs. two more than the simple interest for the same period.If the rate of interest is 5% per year,then the capital would be
a. Rs. 800
b. Rs. 840
c. Rs. 880
d. Rs. 882
4. An amount on compound interest becomes double in four years. It will become eight times in
a. 8 years
b. 12 years
c. 16 years
d. 20 years
5. Twenty litres of a mixture contains milk and water in the ratio of 5 : 3. If four litres of this mixture is replaced by four litres of milk, then the ratio of the milk to that of the water in the new mixture will be
a. 5 : 3
b. 4 : 3
c. 7 : 3
d. 2 : 3
6.
is equal to
a. 6(2/3)
b. 3(1/2)
c. 6
d. 3
7. If a, b, c, …., x, y, z are 26 natural numbers, then the value of (x – a)(x – b) (x – c) …. (x – y) (x – z) is
a. 0
b. 1
c. 13
d. 26
8. 
a. 3m
b. 4m
c. m
d. 5m
9. The expression 
=
a. 1
b. 1/2
c. 5/12
d. 7/9
10. If Rs. 370 are divided among 10 men, 12 women and 20 boys such that each man gets an amount equal to that received by one woman and one boy together and that each woman gets twice the amount received by a boy,then the amount received by 10 men would be
a. Rs. 100
b. Rs. 150
c. Rs. 120
d. Rs. 130
11. Consider the following statements : For any positive integer n, the number 
 is divisible by
1. 9 for n = odd only.
2. 9 for n = even only.
3. 11 for n = odd only.
4. 11 for n = even only.
5. 9 for n = odd or even.
Which of the above statements are correct ?
a. 1 and 3
b. 2 and 3
c. 1 and 4
d. 4 and 5
12. A prime number N, in the range 10 to 50, remains unchanged when its digits are reversed. The square of such a number is
a. 1936
b. 1089
c. 484
d. 121
13. In a six-digit number, the sum of the digits in the even places is 9 and the sum of the digits in the odd places is 20. All such numbers are divisible by
a. 7
b. 9
c. 6
d. 11
14. Which one of the following numbers is divisible by 15 ?
a. 30560
b. 29515
c. 23755
d. 17325
15. If m and n are positive integers, then the digit in the unit’s place of 
 is always
a. 1
b. 5
c. 6
d. n + m
16. If 
x+y=3 and x-y=1 then x and y are respectively
a. 100 and 10
b. 10 and 100
c. 1000 and 100
d. 100 and 1000
17. 
a. 
b. 1+
c. 
d. 1+
18. If log 2 = 0.3010, then the number of digits in  
 is
a. 20
b. 32
c. 128
d. 301
19. If 2(1/2) minutes is represented by 30 units, then the unit of time is
a. 5 sec
b. 6 sec
c. 7 sec
d. 8 sec
20. The expression 
 is a polynomial of degree n
a. Only when n is a positive integer
b. If n is a negative integer and an ≠0
c. If n is a positive integer and a0 ≠0
d. If n is any integer
21. The area of the region bounded by Ix − 1I ≤ 1, Iy − 2I ≤ 2 and 2x + y = 4 is
a. 1 unit
b. 2 units
c. 3 units
d. 4 units
22. A lady has 25-paise coins and 37.50-paise coins. If in all, she has 80 coins totalling Rs. 21, then the difference between the number of 25-paise and 50-paise coins is
a. 4
b. 8
c. 72
d. 76
23. The cost price of a table and a 38.chair together is Rs. 430. If the table costs 15% more than the chair, then the cost (in rupees) of the table and the chair are respectively
a. 196 and 175
b. 230 and 200
c. 200 and 170
d. 240 and 190
24. The sum of the digits of a two.digit number is 9. If the number obtained by reversing the digits of the number exceeds the given number by 27, then the number is
a. 54
b. 45
c. 36
d. 27
25. The set of linear inequations, x + y < 0, x > 0, y > 0 has
a. 3 solutions
b. 1 solutions
c. No solutions
d. An infinite number of solutions
