For English speaking people, I don't think it is necessary to learn Chinese for business.
There is many Chinese who could speak English in Hong Kong and China. The girls in China or Hong Kong are very willing to be the translators or even wives of foreigners. English speaking people just employ a translator and all problems could be solved.
Moreover, Chinese word is difficult to learn, especially for simplified Chinese. The figures of Simplified Chinese has less logical meaning than traditional Chinese. Foreigners need to remember most of the Chinese word without logical linkage to the meaning.
The most problems in doing business in China is not languages, but the regulations and relationship in China. If English speaking people have no relationship in China and know nothing about Chinese regulation, it is better not to invest in China even you know Chinese languages.