Question

The difference between the sum of first 100 natural numbers and the sum of even numbers from 1 to 100.

• A. 2200
• B. 2400
• C. 2500
• D. 2700

Answer 1

The correct option is C

2500

Sum of first 100 natural numbers = $\frac{100}{2}(2+99)=5050$

Sum of even numbers from 1 to 100, there are 50 even numbers between 1 and 100.

So, the sum of the 50 even numbers between 1 and 100 $=\frac{50}{2}(2\times 2+49\times 2)=2550$.
$=\frac{50}{2}(2\times 2+49\times 2)=2550$.

So, the difference is 5050 - 2550 = 2500