10th Class Mathematics Statistics Question Bank Statistics

  • question_answer
    The average monthly income (in Rs.) of certain agricultural workers is S and that of other workers is T. The number of agricultural workers are 11 times that of other workers. Then the average monthly income (in Rs.) of all the workers is __. 

    A)  \[\frac{S+T}{2}\]                 

    B)  \[\frac{S+11T}{2}\]             

    C)  \[\frac{1}{11S}+T\]             

    D)  \[\frac{11S+T}{12}\]

    Correct Answer: D

    Solution :

    Let the number of agricultural and other workers be \[{{n}_{1}}\] and \[{{n}_{2}}\] \[\therefore \]   \[{{n}_{1}}=11\,{{n}_{2}}\]                          ...(i) Sum of monthly income of agricultural workers =\[=s\,{{n}_{1}}\] Sum of monthly income of other workers \[=T\,{{n}_{2}}\] Sum of monthly income of all workers \[=S\,{{n}_{1}}+T\,{{n}_{2}}\] \[\therefore \]  Average monthly income of all workers \[=\frac{S{{n}_{1}}+T{{n}_{2}}}{{{n}_{1}}+{{n}_{2}}}=\frac{S(11{{n}_{2}})+T{{n}_{2}}}{11{{n}_{2}}+{{n}_{2}}}\] \[=\frac{{{n}_{2}}(11S+T)}{{{n}_{2}}(11+1)}=\frac{11S+T}{12}\]


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