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【简答题】
市场上某品牌的智能手机由甲、乙、丙三个厂家同时供货,它们的供货量分别占总量的50%,25%,25%,三个厂家产品的次品率依次为3%,2%,4%。 若在市场上随意购买一件该品牌的智能手机,求 (1)买到次品的概率是多少? (2)若已知买到的是次品,求它是丙厂生产的概率。
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举一反三
【单选题】Tommy’s parents looked _______ when they saw his excellent exam results.
A.
happy
B.
happier
C.
happiness
D.
unhappy
【单选题】Tom＿＿＿＿＿＿＿show his exam results to his parents.
A.
dare not
B.
dared
C.
dare to
D.
dares not to
【单选题】At the ______ exam results, his mother got ______ with him. [ ]
A.
discouraging; discouraging
B.
discouraged; discouraging
C.
discouraging; discouraged
D.
discouraged; discouraged
【单选题】Steven’s exam results put him ________ the top ten students in his grade.
A.
among
B.
between
C.
in
D.
at
【单选题】John ______ he could improve his exam results, but he did not have enough time to study.
A.
knows how
B.
knows that
C.
knew how
D.
knew that
【单选题】每一个JavaBean都有一个生存范围,JavaBean只有在它定义的范围内才能使用,若没有指明,JavaBean的缺省使用范围是_____。
A.
page
B.
request
C.
session
D.
application
【单选题】John ______ be could improve his exam results, but he did not have enough time to study.
A.
knows how
B.
knows that
C.
knew how
D.
knew that
【简答题】钢制齿轮，由于渗碳淬火后热处理变形大，一般需经过______加工，否则不能保证齿轮精度。
【单选题】在进行精密水准测量时,会受到各种误差的影响。为了减弱( )对观测高差的影响,应使前、后视距尽量相等 ,并使视线离地面有足够的高度。
A.
大气垂直折光的影响
B.
仪器和水准标尺垂直位移的影响
C.
温度变化对 i角误差的影响
D.
i角误差的影响
相关题目：
【单选题】Tom＿＿＿＿＿＿＿show his exam results to his parents.
A.
dare not
B.
dared
C.
dare to
D.
dares not to