CDS Exam (II)- 2022 - Elementary Mathematics Defence Question Paper

CDS Previous Year Question Papers Question Papers
CDS Exam (II)- 2022 - Elementary Mathematics

CDS Exam (II)- 2022 - Elementary Mathematics Defence Questions

11.
Consider the following statements:
1. \( x^{4}(y - z) + y^{4}(z - x) + z^{4}(x - y) \) is positive if \( x > y > z \).
2. \( x^{4}(y - z) + y^{4}(z - x) + z^{4}(x - y) \) is negative if \( x < y < z \).
Which of the above statements is/are correct?
A.
Only 1
B.
Only 2
C.
Both 1 and 2
D.
Neither 1 nor 2
ANSWER :
C. Both 1 and 2
12.
What is \( \frac{x^{6} - 24x^{4} + 144x^{2}}{(x^{2} + 4\sqrt{3}x + 12)(x - 2\sqrt{3})^{2}} \) equal to?
A.
\( x^{2} \)
B.
\( x^{2} - 2 \)
C.
\( x^{2} + 2\sqrt{3} \)
D.
\( x^{2} - 2\sqrt{3} \)
ANSWER :
A. \( x^{2} \)
13.
X and Y can do a piece of work in 45 days and 40 days respectively. They begin to work together, but X leaves after n days and then Y completes the remaining work in 23 days. What is n equal to?
A.
8
B.
9
C.
10
D.
12
ANSWER :
B. 9
14.
480 persons working 10 hours per day complete one-fourth of a work in 10 days. How many additional persons are to be employed in order to complete the remaining work in 20 days, working 8 hours per day?
A.
400
B.
420
C.
480
D.
500
ANSWER :
B. 420
15.
12 women and 16 men can do a piece of work in 5 days. 13 women and 24 men can do it in 4 days. How long will 25 women and 50 men take to do it?
A.
1 day
B.
2 days
C.
3 days
D.
4 days
ANSWER :
B. 2 days
16.
There are two stations X and Y, 1320 km apart. A train starts from station X at 6 a.m. and moves at an average speed of 60 km/hr. At 2 p.m. another train starts from Y towards X and moves at an average speed of 80 km/hr. When do they meet?
A.
6 p.m.
B.
7 p.m.
C.
8 p.m.
D.
9 p.m.
ANSWER :
C. 8 p.m.
17.
Two glasses of equal volume are filled with a mixture of alcohol and water in the ratio 3 : 2 and 4 : 1, respectively. These glasses are emptied into a third glass. What is the ratio of alcohol and water in the third glass?
A.
5 : 4
B.
7 : 2
C.
7 : 3
D.
7 : 4
ANSWER :
C. 7 : 3
18.
If x is the HCF and y is the LCM of \( \frac{3}{5}, \frac{6}{25}, \frac{9}{20}, \frac{27}{50} \), then which one of the following is correct?
A.
y = 90x
B.
y = 180x
C.
y = 270x
D.
y = 360x
ANSWER :
D. y = 360x
19.
There are two natural numbers x and y, where \( x > y \). When x is divided by 6, it leaves the remainder 2 and; when y is divided by 6, it leaves the remainder 3. What is the remainder when (x - y) is divided by 6?
A.
1
B.
3
C.
5
D.
Remainder cannot be determined
ANSWER :
C. 5
20.
The value of a 2-digit number is 5 times the sum of the digits. What is the product of the digits?
A.
15
B.
18
C.
20
D.
27
ANSWER :
C. 20