Question

. 6216 coins are arranged in a triangular form with one coin in the first row, 2 coins in the second row,
3 coins in the third row, 4 coins in the fourth row, and so on to N coins in the Nth row.
The sum of the digits of the last row number in this arrangement is .

Answer 1

Step-by-step explanation:

stepwise solution of the problem is enclosed.