 <translate> Give the step-by-step reasoning process and then the final answer. Matias is a salesman in a bookstore. He sold 7 books on Tuesday and three times as many on Wednesday. If the sales from Wednesday were tripled on Thursday, how many books did Matias sell during these three days combined? <yor> Ṣàlàyé bí wọ́n ṣe ń ronú lẹ́ẹ̀kan-lẹ́ẹ̀kan, kó o sì wá sọ ìdáhùn tó o máa fún wọn. Ọ̀kan lára àwọn tó ń ta ìwé ni Matias. Ó ta ìwé méje lọ́jọ́ Tuesday, ó sì ta iye yẹn ní ìlọ́po mẹ́ta lọ́jọ́ Wednesday. Tó bá jẹ́ pé iye ìwé tí wọ́n tà ní ọjọ́ Wednesday ti di ìlọ́po mẹ́ta lọ́jọ́ Thursday, iye ìwé wo ni Matias ta láàárín ọjọ́ mẹ́ta yìí lápapọ̀? 