An arrangement of marbles has 12 marbles in the first row and 10 rows in all. in each successive row one marble is added. what is the explicit rule for this situation, and how many marbles will be in the 10th row? drag and drop the answers into the boxes to match the situation. explicit rule number of marbles in the 10th row an = 11 + 11n, an = 12 + n, an = 11 + n, an = 12 + 10n, 19, 20, 21,