CDS Exam (I)- 2026 - Elementary Mathematics Defence Question Paper

CDS Previous Year Question Papers Question Papers
CDS Exam (I)- 2026 - Elementary Mathematics

CDS Exam (I)- 2026 - Elementary Mathematics Defence Questions

31.
Let \( P = N^{2} \) where N is an odd integer. What is the remainder when P is divided by 8?
A.
1
B.
3
C.
5
D.
Cannot be determined due to insufficient data
ANSWER :
A. 1
32.
A reduction of 10% in the price of sugar enables a person to buy 6.2 kg more for ₹2790. What is the reduced price per kilogram?
A.
₹50
B.
₹48
C.
₹45
D.
₹42
ANSWER :
C. ₹45
33.
A single discount which is equivalent to a series of discounts \( p\% \), \( \frac{p}{2}\% \), \( \frac{p}{4}\% \) is 31.6%. What is the value of \( p \)?
A.
24%
B.
20%
C.
18%
D.
16%
ANSWER :
B. 20%
34.
A locomotive engine can go 40 km/hr. Its speed gets reduced by a quantity that varies directly as the square root of the number of wagons attached. It is known that its speed becomes 16 km/hr if 36 wagons are attached. What is the smallest number of wagons with which the engine is unable to move?
A.
100
B.
81
C.
64
D.
49
ANSWER :
A. 100
35.
Two numbers P and Q are such that P : Q = x : y. If 1 is added to both the numbers, the ratio becomes 7 : 10. If 3 is added to both the numbers, the ratio becomes 3 : 4. What is \( (x + y) : (x - y) \) equal to?
A.
-5
B.
-3
C.
3
D.
Cannot be determined due to insufficient data
ANSWER :
A. -5
36.
ABC is a triangle right-angled at C. A semicircle is drawn on AB as diameter. Let P be any point on AC produced such that AP = AB = 10 cm. Further, B and P are joined. If BC = 8 cm, then what is BP equal to?
A.
\( 4\sqrt{5} \) cm
B.
9 cm
C.
10 cm
D.
\( 5\sqrt{5} \) cm
ANSWER :
A. \( 4\sqrt{5} \) cm
37.
All possible groups of 3 distinct numbers from among A, B, C, D and E are formed. If the aggregate of sums of numbers of each group is 120, then what is the arithmetic mean of A, B, C, D and E?
A.
4
B.
5
C.
10
D.
20
ANSWER :
A. 4
38.
The arithmetic mean of 100 observations is 50. If 10 is added to each observation then what will be the new arithmetic mean?
A.
50
B.
55
C.
60
D.
65
ANSWER :
C. 60
39.
The sum of the deviations of a set of \( n \) numbers \( x_{1}, x_{2}, x_{3}, \ldots, x_{n} \) measured from 15 is -90 and the sum of the deviations of the same numbers measured from -3 is 54. What is the arithmetic mean?
A.
3.25
B.
3.50
C.
3.75
D.
4.25
ANSWER :
C. 3.75
40.
The numbers 59, 53, 51, 43, 36, \( (8x + 1) \), \( (x^{2} + 1) \), 13, 12, 9, 7, 3 are written in descending order and their median is 25. What is/are the values of \( x \)?
A.
-12 only
B.
4 only
C.
-12, 4
D.
12, -4
ANSWER :
B. 4 only