2000+15s+(s/100+3.1)*200=900+20s+(s/80+2)*200s=.

问题描述:

2000+15s+(s/100+3.1)*200=900+20s+(s/80+2)*200
s=.

2000+15s+(s/100+3.1)*200=900+20s+(s/80+2)*200
2000+15s+2s+630=900+20s+25s+400
28s=1330
4s=190
s=47.5