De: 2/5x+x+2/3x=3 10。
3 1/ 15x=3 10
x=3 10×( 15/3 1)
∴x= 150
∴ Science and technology book = 150×2/5=60 (this) literature and art book = 150×2/3= 100 (this)
2. Set Party A's crude oil as X kg.
D: 2/3(x-5)=x-40+5。
2/3(x-5)=x-35
2/3x- 10/3=x-35
- 1/3x=-95/3
∴x=95
∴ B crude oil 95-40=55 kg