A certain class bought several pens with a unit price of 1.5 yuan. If these pens are only distributed to girls, each person will get 15 pens on average. If these pens are only distributed to boys, each person will get 10 pens on average. Then distribute these pens equally to the whole class, how much should each person pay.
某班买来单价为1.5元的笔若干支，如果将这些笔只分给女生，平均，每人分得15支，如果将这些笔只分给男生，平均每人分得10支．那么将这些笔平均分给全班同学，每人应该付多少元钱．
<gadget id="calculator">6 * 1.5</gadget>
<output>9</output>

<result>9</result>