根據(jù)圖表中提供的信息解答下列問(wèn)題:
組別 | 成績(jī)分組 | 頻數(shù) |
A | 47.5~59.5 | 2 |
B | 59.5~71.5 | 4 |
C | 71.5~83.5 | a |
D | 83.5~95.5 | 10 |
E | 95.5~107.5 | b |
F | 107.5~120 | 6 |
A(噸) | B(噸) | 合計(jì)(噸) | |
C | 240 | ||
D | x | 260 | |
總計(jì)(噸) | 200 | 300 | 500 |