CDS Exam (II)- 2021 - Elementary Mathematics Defence Question Paper

CDS Previous Year Question Papers Question Papers
CDS Exam (II)- 2021 - Elementary Mathematics

CDS Exam (II)- 2021 - Elementary Mathematics Defence Questions

41.
If \( p \) varies directly as \( q \) and inversely as square of \( r \), what is the percentage increase in \( p \) due to an increase in \( q \) by 20% and a decrease in \( r \) by 20%?
A.
87.5%
B.
85%
C.
82.5%
D.
80%
ANSWER :
A. 87.5%
42.
A person agrees to work for 30 days, on a condition that for every day's work he should receive ₹500, and that for every day's absence from work he should forfeit ₹100. At the end of the time he received ₹11,400. How many days did he work?
A.
20
B.
21
C.
24
D.
25
ANSWER :
C. 24
43.
A person bought a chair and a table for ₹750. He sold the chair at a gain of 5% and the table at a gain of 20%. He gained 16% on the whole. What is original cost of table?
A.
₹400
B.
₹450
C.
₹550
D.
₹600
ANSWER :
C. ₹550
44.
A person rode one-third of a journey at 60 km/hr, one-third at 50 km/hr and the rest at 40 km/hr. Had the person ridden half of the journey at 60 km/hr and the rest at 40 km/hr, he would have taken 4 minutes longer to complete the journey. What distance did the person ride?
A.
180 km
B.
210 km
C.
240 km
D.
300 km
ANSWER :
C. 240 km
45.
A person saves ₹1000 more than he did the previous year. If he saves ₹2000 in the first year, in how many years will he save ₹170000?
A.
16 years
B.
17 years
C.
18 years
D.
19 years
ANSWER :
B. 17 years
46.
What is the minimum value of \( \cos^{3}\theta + \sec^{3}\theta \) where \( 0^{\circ} \leq \theta < 90^{\circ} \)?
A.
0
B.
1
C.
2
D.
None of the above
ANSWER :
C. 2
47.
If \( 14\sin^{2}\theta + 10\cos^{2}\theta = 11 \) where \( 0^{\circ} < \theta < 90^{\circ} \), then what is the value of \( \tan\theta + \cot\theta \)?
A.
\( \frac{4}{\sqrt{3}} \)
B.
\( \frac{2}{\sqrt{3}} \)
C.
\( \sqrt{3} \)
D.
\( 2\sqrt{3} \)
ANSWER :
A. \( \frac{4}{\sqrt{3}} \)
48.
What is \( \frac{\sin^{3}\theta + \cos^{3}\theta}{\sin\theta + \cos\theta} + \frac{\sin^{3}\theta - \cos^{3}\theta}{\sin\theta - \cos\theta} \) equal to?
A.
0
B.
1
C.
2
D.
4
ANSWER :
C. 2
49.
A ladder 10 m long reaches a point 10 m below the top of a vertical flagstaff. From foot of the ladder, the elevation of top of the flagstaff is \( 60^{\circ} \). What is the height of flagstaff?
A.
12 m
B.
15 m
C.
16 m
D.
20 m
ANSWER :
B. 15 m
50.
What is the maximum value of
\( 1 + 2\sin^{2}\theta\cos^{2}\theta - \sin^{4}\theta - \cos^{4}\theta \)
where \( 0^{\circ} < \theta < 90^{\circ} \)?
A.
1
B.
2
C.
3
D.
4
ANSWER :
A. 1