各位學長：

底下這題是個計算題：

An application uses 20, 10 GB devices. A pointer-based full volume replica of the application is required every 6 hours. Each replica will be kept for 24 hours. The data changes by 10% every 4 hours.
How many replica devices are required?

我是這樣想的：

(10*20/6*24*(1.1)^6)/10=141.724, ---142

可是答案是80。不曉得哪裡錯了，再請學長們指導，萬分感謝!!