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What is the unit digit in (4137)754?

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Question:
What is the unit digit in (4137)754?

[A].

1

[B].

3

[C].

7

[D].

9

Answer: Option D

Explanation:

Unit digit in (4137)754 = Unit digit in {[(4137)4]188 x (4137)2}

=Unit digit in { 292915317923361 x 17114769 }

= (1 x 9) = 9

The smallest 3 digit prime number is:

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Question: The smallest 3 digit prime number is:
[A].

101

[B].

103

[C].

109

[D].

113

Answer: Option A

Explanation:

The smallest 3-digit number is 100, which is divisible by 2.

100 is not a prime number.

101 < 11 and 101 is not divisible by any of the prime numbers 2, 3, 5, 7, 11.

101 is a prime number.

Hence 101 is the smallest 3-digit prime number.

Which one of the following is a prime number ?

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Question:
Which one of the following is a prime number ?

[A].

161

[B].

221

[C].

373

[D].

437

Answer: Option C

Explanation:

437 > 22

All prime numbers less than 22 are : 2, 3, 5, 7, 11, 13, 17, 19.

161 is divisible by 7, and 221 is divisible by 13.

373 is not divisible by any of the above prime numbers.

373 is prime.

The sum of first five prime numbers is:

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Question: The sum of first five prime numbers is:
[A].

11

[B].

18

[C].

26

[D].

28

Answer: Option D

Explanation:

Required sum = (2 + 3 + 5 + 7 + 11) = 28.

Note: 1 is not a prime number.

Definition: A prime number (or a prime) is a natural number that has exactly two distinct natural number divisors: 1 and itself.