CDS Exam (I)- 2019 - Elementary Mathematics Defence Question Paper

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CDS Exam (I)- 2019 - Elementary Mathematics

CDS Exam (I)- 2019 - Elementary Mathematics Defence Questions

11.
Radha and Hema are neighbours and study in the same school. Both of them use bicycles to go to the school. Radha's speed is 8 km/hr whereas Hema's speed is 10 km/hr. Hema takes 9 minutes less than Radha to reach the school. How far is the school from the locality of Radha and Hema?
A.
5 km
B.
5.5 km
C.
6 km
D.
6.5 km
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ANSWER :
C. 6 km
12.
Which of the following pair of numbers is the solution of the equation \( 3^{x+1} + 3^{1-x} = 10 \)?
A.
0, 2
B.
0, −2
C.
1, −1
D.
1, 2
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ANSWER :
C. 1, −1
13.
It is given that \( \log_{10} 2 = 0.301 \) and \( \log_{10} 3 = 0.477 \). How many digits are there in \( (108)^{10} \)?
A.
19
B.
20
C.
21
D.
22
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ANSWER :
C. 21
14.
The sum of three prime numbers is 100. If one of them exceeds another by 36, then one of the numbers is
A.
17
B.
29
C.
43
D.
None of the above
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ANSWER :
D. None of the above
15.
If a, b and c are positive integers such that \( \frac{1}{a+\frac{1}{b+\frac{1}{c+\frac{1}{2}}}} = \frac{16}{23} \), then what is the mean of a, b and c?
A.
1
B.
2
C.
1.33
D.
2.33
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ANSWER :
B. 2
16.

Consider the following for the next three (03) items:
In a certain town of population size 1,00,000 three types of newspapers (I, II and III) are available. The percentages of the people in the town who read these papers are as follows:

Newspaper Proportion of readers
I 10%
II 30%
III 5%
Both I and II 8%
Both II and III 4%
Both I and III 2%
All the three (I, II and III) 1%



What is the number of people who read only one newspaper?

A.

20,000

B.

25,000

C.

30,000

D.

35,000

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ANSWER :

A. 20,000

17.
What is the number of people who read at least two newspapers?
A.
12,000
B.
13,000
C.
14,000
D.
15,000
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ANSWER :
A. 12,000
18.
What is the number of people who do not read any of these three newspapers?
A.
62,000
B.
64,000
C.
66,000
D.
68,000
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ANSWER :
D. 68,000
19.
What is the unit place digit in the expansion of \( 7^{73} \)?
A.
1
B.
3
C.
7
D.
9
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ANSWER :
C. 7
20.
Suppose n is a positive integer such that \( \left(n^{2} + 48\right) \) is a perfect square. What is the number of such n?
A.
One
B.
Two
C.
Three
D.
Four
😑 View Answer Error
ANSWER :
C. Three
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