3.单项式-$\frac{2}{5}$a2b3的系数和次数分别是( )
| A. | -$\frac{2}{5}$,2 | B. | $\frac{2}{5}$,3 | C. | -$\frac{2}{5}$,5 | D. | $\frac{2}{5}$,6 |
1.已知xm=2,xn=3,x2m+n=( )
| A. | 12 | B. | 108 | C. | 18 | D. | 36 |
15.一家游泳馆的游泳收费标准为25元/次,若购买会员年卡,可享受如下优惠:
例如,购买A类会员卡,一年内游泳20次,消费50+20×20=450元,若一年内在该游泳馆消费500元,则游泳次数最多的办卡方式是( )
0 297771 297779 297785 297789 297795 297797 297801 297807 297809 297815 297821 297825 297827 297831 297837 297839 297845 297849 297851 297855 297857 297861 297863 297865 297866 297867 297869 297870 297871 297873 297875 297879 297881 297885 297887 297891 297897 297899 297905 297909 297911 297915 297921 297927 297929 297935 297939 297941 297947 297951 297957 297965 366461
| 会员年卡类型 | 办卡费用(元) | 每次游泳收费(元) |
| A类 | 50 | 20 |
| B类 | 150 | 15 |
| C类 | 300 | 10 |
| A. | 购买A类会员年卡 | B. | 购买B类会员年卡 | C. | 购买C类会员年卡 | D. | 不购买会员年卡 |