Question

Using the formula for the sum of first n natural numbers, find 1 + 2 + 3 + ... + 10:

विकल्प

• 45

• 50

• 55

• 60

Answer 1

55

Explanation:

The sum of first n natural numbers = `"n(n+1)"/2`.

 For n = 10: `"10(11)"/2` = `110/2` = 55.