相關X45678910P0020040060的文學知識

問題詳情：某*手*擊所得環數X的分佈列爲：X45678910P0.020.040.060.090.280.290.22則此*手“*擊一次命中環數大於7”的概率爲()A．0.28                               B．0.88C．0.79    ...