1.有五张不透明的卡片,正面的数分别写有3.101001000,$\frac{7}{3}$,π,$\sqrt{6}$,3.$\stackrel{••}{12}$,除正面的数不同外,其余都相同,将它们背面朝上洗匀后,从中随机抽取一张卡片,抽到写有有理数卡片的概率为( )
| A. | $\frac{1}{5}$ | B. | $\frac{2}{5}$ | C. | $\frac{3}{5}$ | D. | $\frac{4}{5}$ |
20.
如图是一个转盘,扇形1,2,3的圆心角分别是60°,70°,150°,任意转动转盘,指针指向扇形4的概率是( )
0 295108 295116 295122 295126 295132 295134 295138 295144 295146 295152 295158 295162 295164 295168 295174 295176 295182 295186 295188 295192 295194 295198 295200 295202 295203 295204 295206 295207 295208 295210 295212 295216 295218 295222 295224 295228 295234 295236 295242 295246 295248 295252 295258 295264 295266 295272 295276 295278 295284 295288 295294 295302 366461
| A. | $\frac{1}{9}$ | B. | $\frac{2}{9}$ | C. | $\frac{1}{3}$ | D. | $\frac{4}{9}$ |