The remaining 1-2/5=3/5.

More than 3/5-2/5= 1/5, that is, 12 pages.

So the whole book is *** 12/( 1/5)=60 pages.

2.

Xiao Ming can copy (1/4)/5= 1/20 every day.

Two people can copy, and it can be completed every day1/20+115 = 7/60.

It takes (7/25)/(7/60) to complete 7/25 = 2.4 days.

3.

(4500-4000)/4500 * 100%= 1 1. 1%

4.

Let the express train speed be x kilometers per hour and the local train speed be 7/8*x kilometers per hour.

According to the meaning of the question,

4*(x-7/8*x)=24*2

X=96 kilometers

7/8*x=7/8*96=84 km

So the express train is 96 kilometers per hour and the local train is 84 kilometers per hour.

The distance between the two places is: 4 * (96+84) = 720km.