CDS I 2020 Elementary Mathematics Previous Year Paper (02-Feb-2020)

Question 1

The number 2 &times; 3 &times; 5 &times; 7 &times; 11 + 1 is

Accepted Answer

a prime number

Answer

not a prime, but power of a prime

Answer

not a power of a prime, but a composite even number

Answer

not a power of a prime, but a composite odd number

Question 2

Two unequal pairs of numbers satisfy the following conditions:(i) The product of the two numbers in each pair is 2160(ii) The HCF of the two numbers in each pair is 12.If x is the mean of the numbers in the first pair and y is the mean of the numbers in the second pair, then what is the mean of x and y?

Accepted Answer

72

Answer

60

Answer

75

Answer

78

Question 3

How many digits are there in (54) 10 ? (Given that log 10 2 = 0.301 and log 10 3 = 0.477)

Accepted Answer

18

Answer

16

Answer

19

Answer

27

Question 4

Which one of the following is a set of solution of the equation ${{\rm{x}}^{\sqrt {\rm{x}} }} = \sqrt[{\rm{n}}]{{{{\rm{x}}^{\rm{x}}}}}$ if n is a positive integer?

Accepted Answer

{1, n2}

Answer

{1, &radic;n}

Answer

{1, n}

Answer

{n, n2}

Question 5

In a competitive examination, 250 students have registered. Out of these, 50 students have registered for Physics, 75 students for Mathematics and 35 students for both Mathematics and Physics. What is the number of students who have registered neither for Physics nor for Mathematics?

Accepted Answer

160

Answer

90

Answer

100

Answer

150

CDS I 2020 Elementary Mathematics Previous Year Paper (02-Feb-2020)

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