Xiaohua finished reading a 100 page story book in four days. On average, Xiaohua read a few parts of the book every day and how much each day

Xiaohua finished reading a 100 page story book in four days. On average, Xiaohua read a few parts of the book every day and how much each day

100 / 4 = 25 (page)
25/100=1/4
On average, Xiaohua reads one fourth of the book every day and 25 pages a day

There are several 1.2.3 prizes. 1.2 prizes account for one-half of the winners, 2.3 prizes account for four fifths, and 1,2,3 prizes account for how many?

The third prize accounts for 1-2% of the winners (1-2 = 1 / 2)
Four fifths - one half = three tenths, which is the second prize
1 / 2 - 3 / 10 = 1 / 5 first prize

In a mathematics competition, there are several first, second and third prize winners. Results the number of first and second prize winners accounts for three-quarters of the total number of winners, the number of second and third prize winners accounts for five sixth of the total number of winners, and the number of second prize winners accounts for what percentage of the total number?

(3/4+5/6)-1=7/12