Question

If the mean of first n natural numbers is 3n/5, then the value of n is

• A. 3
• B. 5
• C. 4
• D. 6

Answer 1

Answer:

B. 5

Sum of natural numbers = n(n + 1)/2

Given, mean = 3n/5

Mean = sum of natural numbers/n

3n/5 = n(n + 1)/2n

3n/5 = (n + 1)/2

6n = 5n + 5

n = 5