1. Actual donation from junior high school (1+30%) * a =1.3a.

Actual donation of senior high school (1+10%) * 2a = 2.2a.

Actual school donation1.3a+2.2a = 3.5a.

2.2.2a- 1.3a=900

a= 1000

Then1.3a =1.3 *1000 =1300 copies.

2.2a = 2.2 *1000 = 2,200 copies.

In fact, junior high school donated 1300 copies and senior high school donated 2200 copies.