计算题

1. What percentage of area is shaded?

Answer: _                                                          .

2. If a group of 6 people have an average age of 21,  and each person is half the age of the next person,

    what are the ages of the 6 people?

Answer: _                                                           .

开户单位在购销活动中，不得对现金结算给予比转账结算优惠的待遇，不得只收现金而拒收（）和其他转账结算凭证。

A.支票

B.银行本票

C.银行汇票

D.商业汇票