Solution: Let's assume that in the first year A produced X kilograms of rice. In the first year, B produced 10-x ten thousand Jin of rice.
x( 1+ 10%)+( 10-x)( 1+ 15%)= 10x( 1+ 12%)
1. 1x+ 1 1.5- 1. 15x = 1 1.2
0.05x=0.3
x=6
The yield of rice in the first year B: 10-6=4 (ten thousand Jin)
Rice yield in the second year: 6x( 1+ 10%)=6.6 (ten thousand Jin).
Rice yield in the second year: 4x( 1+ 15%)=4.6 (ten thousand Jin).
2. A school originally planned to donate 3000 books to schools in Sichuan disaster area, and the students responded well. Results 3780 books were actually donated, including 20% for junior high school and 30% for senior high school. How many books were originally planned to donate to junior high school and senior high school?
Xiegao Middle School originally planned to send X books, and junior high school originally planned to send 3000-x books.
(3000-x)( 1+20%)+x( 1+30%)= 3780
3600- 1.2x+ 1.3x = 3780
0. 1x= 180
x= 1800
Junior high school originally planned to give 3000- 1800= 1200 books.