数学题：一条公路，甲队修完要10天，乙队修完要8天。两队合修4天后，还剩下5000米，这条路共长多少米？

数学题解答：把这条公路看作“1”。

甲队每天修：1/10

乙队每天修：1/8

两队4天共修：(1/10 + 1/8) × 4 ＝9/10

还剩：1 – 9/10 = 1/10

剩下的5000米就是这条公路的1/10，所以这条公路长：

5000 ÷ 1/10 = 50000（米）

推荐阅读：
Is Malaysia finally cleaning up corruption? I think not.　 How to use ‘Answer the Public’ to Create Unmissable Blog Posts　 A Guide to Handling Negative Comments and Reviews　 The Best Link Building Methods For Your Website　 How To Use Twitter To Get New Clients　 How to Turn Your Best Blog Posts Into Even Better Videos　 Why You Need Influencers for Your Brand In 2019　 How to Use a Blog to Increase Ecommerce Sales　 Why conducting a website audit is important　 How to Write a Great Blog Post for a Global Audience