CDS Exam (I)- 2023 - Elementary Mathematics Defence Question Paper

CDS Previous Year Question Papers Question Papers
CDS Exam (I)- 2023 - Elementary Mathematics

CDS Exam (I)- 2023 - Elementary Mathematics Defence Questions

11.
If a, b, c, d, e and f satisfy \( 2a = 3b = 6c = 9d = 12e = 18f \), then what is the value of \( \frac{a + b}{c + d + e + f} \)?
A.
\( \frac{4}{7} \)
B.
2
C.
\( \frac{5}{2} \)
D.
\( \frac{9}{2} \)
ANSWER :
B. 2
12.
If a, b, c are non-zero real numbers such that a + b + c = 0, then what are the roots of the equation \( ax^{2} + bx + c = 0 \)?
A.
\( 2, 1 + \frac{c}{a} \)
B.
\( 1, \frac{a}{c} \)
C.
\( 1, \frac{c}{a} \)
D.
\( 2, \frac{c}{a} - 1 \)
ANSWER :
C. \( 1, \frac{c}{a} \)
13.
Twelve percent of bananas bought by a fruit vendor got lost during transportation. On selling the remaining bananas, the vendor's overall profit turned out to be 4%. If the vendor had not lost any bananas and had sold them at the price of the remaining bananas, what would have been his profit percentage?
A.
\( 8\frac{1}{9} \)%
B.
\( 9\frac{1}{11} \)%
C.
\( 18\frac{2}{11} \)%
D.
None of the above
ANSWER :
C. \( 18\frac{2}{11} \)%
14.
If the positive square root of \( (5 + 3\sqrt{2})(5 - 3\sqrt{2}) \) is \( \alpha \), then what is the positive square root of \( 8 + 2\alpha \)?
A.
\( 2 + \sqrt{3} \)
B.
\( 3 - \sqrt{2} \)
C.
\( \sqrt{7} - 1 \)
D.
\( \sqrt{7} + 1 \)
ANSWER :
D. \( \sqrt{7} + 1 \)
15.
When every even power of every odd integer (greater than 1) is divided by 8, what is the remainder?
A.
3
B.
2
C.
1
D.
The remainder is not necessarily 1.
ANSWER :
C. 1
16.
Consider the following statements:
1. If n is a natural number, then the number \( \frac{n(n^{2} + 2)}{3} \) is also a natural number.
2. If m is an odd integer, then the number \( \frac{m^{4} + 4m^{2} + 11}{16} \) is an integer.
Which of the statements given above is/are correct?
A.
1 only
B.
2 only
C.
Both 1 and 2
D.
Neither 1 nor 2
ANSWER :
C. Both 1 and 2
17.
It is given that 5 does not divide n - 1, n and n + 1, where n is a positive integer. Which one of the following is correct?
A.
5 divides \( (n^{2} + 1) \)
B.
5 divides \( (n^{2} - 1) \)
C.
5 divides \( (n^{2} + n) \)
D.
5 divides \( (n^{2} - n) \)
ANSWER :
A. 5 divides \( (n^{2} + 1) \)
18.
What is the largest 5-digit number, which leaves remainder 7, when divided by 18 as well as by 11?
A.
99981
B.
99988
C.
99997
D.
99999
ANSWER :
C. 99997
19.
In a business dealing, A owes B ₹ 20,000 payable after 5 years, whereas B owes A ₹ 12,000 payable after 4 years. They want to settle it now at the rate of 5% simple interest. Who gives how much money in this settlement?
A.
Both are at par
B.
B gives ₹ 6,000 to A
C.
A gives ₹ 6,000 to B
D.
A gives ₹ 4,000 to B
ANSWER :
C. A gives ₹ 6,000 to B
20.
Average marks in Mathematics of Section A comprising 30 students is 65 and that of Section B comprising 35 students is 70. What are the average marks (approximately) of both the sections if it was detected later that an entry of 47 marks was wrongly made as 74?
A.
67.28
B.
67.58
C.
68.11
D.
68.63
ANSWER :
A. 67.28