CDS Exam (I)- 2020 - Elementary Mathematics Defence Question Paper

CDS Previous Year Question Papers Question Papers
CDS Exam (I)- 2020 - Elementary Mathematics

CDS Exam (I)- 2020 - Elementary Mathematics Defence Questions

1.
The number \( 2 \times 3 \times 5 \times 7 \times 11 + 1 \) is
A.
a prime number
B.
not a prime, but power of a prime
C.
not a power of a prime, but a composite even number
D.
not a power of a prime, but a composite odd number
😑 View Answer Error
ANSWER :
A. a prime number
2.
Two unequal pairs of numbers satisfy the following conditions:
(i) The product of the two numbers in each pair is 2160
(ii) The HCF of the two numbers in each pair is 12.
If \( x \) is the mean of the numbers in the first pair and \( y \) is the mean of the numbers in the second pair, then what is the mean of \( x \) and \( y \)?
A.
60
B.
72
C.
75
D.
78
😑 View Answer Error
ANSWER :
B. 72
3.
How many digits are there in \( (54)^{10} \)? (Given that \( \log_{10} 2 = 0.301 \) and \( \log_{10} 3 = 0.477 \))
A.
16
B.
18
C.
19
D.
27
😑 View Answer Error
ANSWER :
B. 18
4.
Which one of the following is a set of solutions of the equation \( x^{\sqrt{x}} = \sqrt[n]{x^{x}} \), if \( n \) is a positive integer?
A.
\( \left\{1, n^{2}\right\} \)
B.
\( \left\{1, \sqrt{n}\right\} \)
C.
\( \left\{1, n\right\} \)
D.
\( \left\{n, n^{2}\right\} \)
😑 View Answer Error
ANSWER :
A. \( \left\{1, n^{2}\right\} \)
5.
In a competitive examination, 250 students have registered. Out of these, 50 students have registered for Physics, 75 students for Mathematics and 35 students for both Mathematics and Physics. What is the number of students who have registered neither for Physics nor for Mathematics?
A.
90
B.
100
C.
150
D.
160
😑 View Answer Error
ANSWER :
D. 160
6.
If the sum of the digits of a number \( 10^{n} - 1 \), where \( n \) is a natural number, is equal to 3798, then what is the value of \( n \)?
A.
421
B.
422
C.
423
D.
424
😑 View Answer Error
ANSWER :
B. 422
7.
Which one of the following is the largest number among \( 2222^{2}, 222^{22}, 22^{222}, 2^{2222} \)?
A.
\( 2^{2222} \)
B.
\( 22^{222} \)
C.
\( 222^{22} \)
D.
\( 2222^{2} \)
😑 View Answer Error
ANSWER :
A. \( 2^{2222} \)
8.
If \( m \) is the number of prime numbers between 0 and 50; and \( n \) is the number of prime numbers between 50 and 100, then what is \( (m - n) \) equal to?
A.
4
B.
5
C.
6
D.
7
😑 View Answer Error
ANSWER :
B. 5
9.
If \( \frac{a}{b} = \frac{1}{3}, \frac{b}{c} = 2, \frac{c}{d} = \frac{1}{2}, \frac{d}{e} = 3 \) and \( \frac{e}{f} = \frac{1}{4} \), then what is the value of \( \frac{abc}{def} \)?
A.
\( \frac{1}{4} \)
B.
\( \frac{3}{4} \)
C.
\( \frac{3}{8} \)
D.
\( \frac{27}{4} \)
😑 View Answer Error
ANSWER :
C. \( \frac{3}{8} \)
10.
Which one of the following is the largest divisor of \( 3^{x} + 3^{x+1} + 3^{x+2} \), if \( x \) is any natural number?
A.
3
B.
13
C.
39
D.
117
😑 View Answer Error
ANSWER :
C. 39
Prev Next page