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8th Class Mathematics Related to Competitive Exam Question Bank Arithmetic

  • question_answer
    A bag contains Rs600 in the form of 1 - rupee, 50 paise and 25 paise coins in the ratio 3 :4: 12, the number of 25 paise coins is:

    A) 600                       

    B) 900

    C) 1200                     

    D) 1376                         

    Correct Answer: B

    Solution :

    Let x = 1 rupee coin, y = 50 paise coin, z = 25 paise coin \[SP=\frac{5}{10}=\frac{1}{2};CP=?;gain%=20%\] \[gain%=\frac{SP-CP}{CP}\times 100\] \[20=\frac{\frac{1}{2}-CP}{CP}\times 100\] \[=\frac{1}{20}\]         ?.(1) Also, let x = 3k, y = 4k, z = 12k \[\therefore \] From (1) \[=\frac{1}{x}\] \[\therefore \] \[\frac{1}{x}+\frac{0.3}{x}=\frac{1}{20}\] \[\Rightarrow \] \[\frac{1.3}{x}=\frac{1}{20}\] \[\Rightarrow \] \[k=\frac{2400}{32}=75\] \[\Rightarrow \] Number of 25-paise coin \[x=26\]


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