When Xiao Hong read a story book, she read 5 / 1 of the total pages on the first day, 15 pages less than the first day on the second day, and 3 / 1 of the total pages in two days, Xiao Hong read a story book. On the first day, she read 5 / 1 of the total pages. On the second day, she read 15 pages less than on the first day. On the second day, she just read 3 / 1 of the total pages. How many pages did she read in the two days?

When Xiao Hong read a story book, she read 5 / 1 of the total pages on the first day, 15 pages less than the first day on the second day, and 3 / 1 of the total pages in two days, Xiao Hong read a story book. On the first day, she read 5 / 1 of the total pages. On the second day, she read 15 pages less than on the first day. On the second day, she just read 3 / 1 of the total pages. How many pages did she read in the two days?

15 ÷ (1 / 5 + 1 / 5-1 / 3) × (1 / 3) = 75 (page)