Question

Find the sum of the digits of the number 6+66+666+6666 + ... +666...66, where the last number contains 100 digits.

Answer 1

30300

Explanation:

Actually, se have an arithmetic progression:

6, 12, 18, 24... 600

`S = ((6 + 600).100)/(2) \\\\ S = (6 + 600).50 \\\ S = 300 + 30000 \\\ S = 30300`

I hope I've helped you.