Examsnet
Unconfined exams practice
Home
Exams
Banking Entrance Exams
CUET Exam Papers
Defence Exams
Engineering Exams
Finance Entrance Exams
GATE Exam Practice
Insurance Exams
International Exams
JEE Exams
LAW Entrance Exams
MBA Entrance Exams
MCA Entrance Exams
Medical Entrance Exams
Other Entrance Exams
Police Exams
Public Service Commission (PSC)
RRB Entrance Exams
SSC Exams
State Govt Exams
Subjectwise Practice
Teacher Exams
SET Exams(State Eligibility Test)
UPSC Entrance Exams
Aptitude
Algebra and Higher Mathematics
Arithmetic
Commercial Mathematics
Data Based Mathematics
Geometry and Mensuration
Number System and Numeracy
Problem Solving
Board Exams
Andhra
Bihar
CBSE
Gujarat
Haryana
ICSE
Jammu and Kashmir
Karnataka
Kerala
Madhya Pradesh
Maharashtra
Odisha
Tamil Nadu
Telangana
Uttar Pradesh
English
Competitive English
Certifications
Technical
Cloud Tech Certifications
Security Tech Certifications
Management
IT Infrastructure
More
About
Careers
Contact Us
Our Apps
Privacy
Test Index
UPSC CDS 2 2021 Math Paper
Show Para
Hide Para
Share question:
© examsnet.com
Question : 34
Total: 100
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
∘
. What is the height of flagstaff ?
12
m
15
m
16
m
20
m
Validate
Solution:
👈: Video Solution
Let OQ be a ladder.
∴
O
Q
=
10
m
Some part of Flagstaff
Q
R
=
10
m
Now,
Q
R
=
Q
O
=
10
m
So,
ln
∆
O
P
R
⇒
∠
R
=
30
∘
∵
O
R
=
O
Q
⇒
∠
R
O
Q
=
∠
O
R
Q
Let
P
Q
=
h
∵
tan
60
∘
=
P
R
O
P
⇒
√
3
=
10
+
h
O
P
⇒
O
P
=
10
+
h
√
3
. . . (ii)
∵
tan
30
∘
=
h
O
P
⇒
O
P
=
h
(
1
∕
√
3
)
=
√
3
h
. . . (ii)
From Eq. (i) and Eq. (ii), we get
10
+
h
√
3
=
√
3
h
⇒
10
+
h
=
3
h
⇒
10
=
2
h
⇒
h
=
5
m
Height of flagstaff
=
h
+
10
=
5
+
10
=
15
m
Hence, the height of the flagstaff is
15
m
.
© examsnet.com
Go to Question:
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
Prev Question
Next Question