CSATNumber System & SeriesArithmetic of Prime Numbers2024

Consider the following statements in respect of the sum S = x + y + z, where x, y and z are distinct prime numbers each less than 10: 1. 1. The unit digit of S can be 0. 2. 2. The unit digit of S can be 9. 3. 3. The unit digit of S can be 5. Which of the statements given above are correct?

A

(a) 1 and 2 only

B

(b) 2 and 3 only

C

(c) 1 and 3 only

D

(d) 1, 2 and 3

Correct Answer: Option C

Explanation

1. First, I identify the 'distinct prime numbers less than 10'. Based on the definition of primes [87], the set is **{2, 3, 5, 7}**. 2. The question asks about the sum S of three of these numbers. Since the s

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