10min
20min
30min
40min
50min
甲
20.5%
39.0%
54.5%
60.0%
乙
23.5%
44.5%
61.0%
66.8%
x
丙
25.0%
45.5%
63.8%
74.0%
80.0%
下列说法正确的是( )