(1)There were still 80 pages left. (2)The remaining pages had to be read within four days, an average of 80 pages per day. This was equivalent to 80/170 = 05 days per page. Therefore, in the remaining 80 pages, you need to look at 80/05 = 16 days, 80/05 = 16 days, 80/05 = 16 days, and 80/05 = 24 days (rounded to two decimals). The final answer was that it took him 16 + 24 = 40 days to read the remaining 80 pages on the 16th and 24th days.