Because it was felt that a school day would last at least eight hours, and you wanted the child to have the ability to use the laptop for at least one full day without having to recharge it.
というのも学校の１日は 少なくとも８時間あり 子供にはノートPCと一緒に １日中過ごさせてあげたいでしょう バッテリーの充電なしにね