Sum of first 20 positive integers will be :

Options

A. 180
B. 190
C. 200
D. 210

Answer

To find the sum of the first 20 positive integers, we can use the formula for the sum of the first n positive integers, which is given by:

\[ S_n = \frac{n(n + 1)}{2} \]

where \( S_n \) is the sum of the first n integers and \( n \) is the number of integers.

**Step 1: Identify n**
Here, we need to find the sum of the first 20 positive integers, so we set \( n = 20 \).

**Step 2: Substitute n into the formula**
Now we substitute \( n \) into the formula:

\[ S_{20} = \frac{20(20 + 1)}{2} \]

**Step 3: Simplify the expression**
Next, we simplify the expression inside the parentheses:

\[ S_{20} = \frac{20 \times 21}{2} \]

**Step 4: Calculate the multiplication**
Now we perform the multiplication:

\[ 20 \times 21 = 420 \]

**Step 5: Divide by 2**
Finally, we divide by 2:

\[ S_{20} = \frac{420}{2} = 210 \]

Thus, the sum of the first 20 positive integers is \( 210 \).

**Final Answer:**
The sum of the first 20 positive integers is \( 210 \).

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