I'd like to change some RMB，since I need some RMB to pay my employees. 我想换些人民币，因为我需要一些人民币来付给我的职员。

What's today's rate between the U.S. dollar and the RMB Yuan? 今天美元和人民币之间的汇率是多少?

One hundred U.S. dollars is equal to seven hundred and forty-three RMB Yuan by the bank's buying rate today 中国银行今天100美元对人民币的买入价为人民币743元。

I suggest you change your pound into RMB first,then change your RMB into U.S. dollar.It's more beneficial to you. 我建议您先把英镑换成人民币，然后再把人民币换成美元，这样对您更有利。

Thank you for your suggestion,but why? 谢谢你的建议，但为什么呢?