Question

Sum of all prime numbers less than 50 is

• A. more than 500
• B. less than 200
• C. a prime number
• D. an even number

Hint:

List the 15 primes below 50 and add them; check the total against each statement rather than guessing.

Answer 1

The Correct Option is D

Step 1: List all primes below 50.
A prime number has exactly two factors, 1 and itself. The primes less than 50 are:
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47.
That is 15 primes in total.

Step 2: Add them up in small groups.
\[ 2+3+5+7+11 = 28 \]
\[ 13+17+19+23+29 = 101 \]
\[ 31+37+41+43+47 = 199 \]

Step 3: Add the group totals.
\[ 28 + 101 + 199 = 328 \]
So the sum of all primes less than 50 is 328.

Step 4: Check each option against 328.
Option (1), more than 500: 328 is less than 500, so this is false.
Option (2), less than 200: 328 is greater than 200, so this is also false.
Option (3), a prime number: 328 is even and greater than 2, so 2 divides it, meaning it has more than two factors and is not prime. False.
Option (4), an even number: 328 divided by 2 is 164, a whole number, so 328 is even. True.

Final Answer:
The sum, 328, is an even number.
\[ \boxed{328, \text{ an even number}} \]