Thousands of taxi drivers in Shenyang, Liaoning Province, reportedly blocked streets with their vehicles on Sunday in protest against unlicensed vehicles using taxi-hiring apps(打车软件) and apps-based car rental companies providing passenger services, including high-end cars. Although the drivers also complained about the withdrawal of the fuel subsidy (补贴) by the government, their main complaint was the loss of business because of the rising number of Internet-based car services companies.

    On Wednesday, news reports came that Beijing transport authorities will take measures to stop the illegal “taxi business” of private cars through the newly rising Internet apps, following the footsteps of Shenyang and Nanjing.

It is not yet clear how the Shenyang city government will handle the issue and whether it will declare the services offered by market leaders such as Didi Dache, a taxi-hiring app provider backed by Tencent Holdings, and Kuaidi Dache illegal. But Shanghai transport regulators have set a rule, by banning Didi Zhuanche, or car services offered by Didi Dache in December.

    Such regulations will cause a setback to the car-hiring companies and investors that are waiting to cash in on the potentially booming business. Just last month, Didi Dache got $700 million in funding from global investors, including Singapore state investment company Temasek Holdings, Russian investment company DST Global and Tencent. Besides, the market is uncertain that Kuaidi Dache is about to finalize its latest round of funding after getting $800 million from global investors.

    Regulatory uncertainties, however, could cast a shadow on the future of the Internet-based car-hiring services, which have become popular in most of China's big cities. To be fair, these companies' business model is anything but bad. For example, Didi Zhuanche works side by side with established car rental companies to provide high-end car service mainly for businesspeople through the Internet and mobile phone apps.

    Every link in this business model chain has legal companies and services. Therefore, it is hard to define it as illegal and ban it.

某班50名学生在一次数学测试中，成绩全部介于50与100之间，将测试结果按如下方式分成五组：第一组50，60），第二组60，70），…，第五组90，100．如图是按上述分组方法得到的频率分布直方图．

（Ⅰ）由频率分布直方图估计50名学生数学成绩的中位数和平均数；

（Ⅱ）从测试成绩在50，60)∪90，100内的所有学生中随机抽取两名同学，设其测试成绩分别为m，n，求事件 “|m-n|＞10”的概率。

在△ABC中，若a=n²﹣1，b=2n，c=n²+1，则△ABC是（　　）

我国全部位于热带的省区是（    ）