CDS Exam (I)- 2025 - Elementary Mathematics Defence Question Paper

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CDS Exam (I)- 2025 - Elementary Mathematics

CDS Exam (I)- 2025 - Elementary Mathematics Defence Questions

1.
A real number M is squared to give the value N. What is the minimum value of (M + N)?
A.
-0.25
B.
-0.50
C.
0
D.
0.25
ANSWER :
A. -0.25
2.
What is the sum of all 3-digit numbers that give a remainder of 5 when they are divided by 50?
A.
9005
B.
9540
C.
9600
D.
9640
ANSWER :
B. 9540
3.
If the average of 64, 69, 72, 75, x lies between 62 and 76 (excluding 62 and 76), then what is the number of possible integer values of x?
A.
68
B.
69
C.
70
D.
71
ANSWER :
B. 69
4.
Let x, y, z be variables such that (x + y + z) = k, where k is a constant. If \( (x + z - y) \times (x - z + y) \) is proportional to yz, then (y + z - x) is proportional to:
A.
x
B.
y
C.
yz
D.
xz
ANSWER :
C. yz
5.
Let p be the remainder when \( 7^{84} \) is divided by 342 and q be the remainder when \( 7^{84} \) is divided by 344. What is (p - q) equal to?
A.
0
B.
1
C.
2
D.
6
ANSWER :
A. 0
6.
N \( = 2^{n} + 1 \) is the smallest 5-digit number which when divided by 2, \( 2^{2} \), \( 2^{3} \), \( 2^{4} \), ..., \( 2^{n} \) leaves a remainder 1. What is the value of n?
A.
12
B.
13
C.
14
D.
15
ANSWER :
C. 14
7.
What is the minimum value of p for which \( \frac{1}{532900} + \frac{p^{2}}{266450} + \frac{p^{4}}{532900} \) is an integer?
A.
729
B.
243
C.
27
D.
1
ANSWER :
C. 27
8.
If \( \alpha \) and \( \beta \) are the roots of the equation \( x + a + b = \frac{abx}{ab + ax + bx} \), then what is \( (\alpha \beta + \alpha + \beta) \) equal to?
A.
ab + a + b
B.
ab - a - b
C.
a + b - ab
D.
-(ab + a + b)
ANSWER :
B. ab - a - b
9.
Consider a 2-digit number N. Let P be the product of the digits of the number. If P is added to square of the digit in the tens place of N, we get 84. If P is added to the square of the digit in the unit place of N, we get 60. What is the value of P + N?
A.
100
B.
110
C.
115
D.
120
ANSWER :
B. 110
10.
A mixture of 100 L contains kerosene and turpentine oil in the ratio 3 : 2. What is the minimum quantity of kerosene in litres (whole number) that should be mixed in the mixture so that the resulting mixture has 20% of kerosene?
A.
10 L
B.
20 L
C.
25 L
D.
Not possible
ANSWER :
D. Not possible