8th Class Mathematics Sample Paper Mathematics Sample Paper - 3

  • question_answer If \[51x\text{ }3\]is a multiple of 9, where x is a digit, then that is the value of x?

    Answer:

    We have, the sum of the digits of 51x 3=5+l+x+3=9+x                                                                          
    Since, 51x 3 is divisible by 9.
    \[\therefore \] (9+x) must be divisible by 9.                                                                                                                                                                               
    \[\therefore \](9 + x) must be equal to 0 or 9 or 18 or 27 or...
    But x is a digit, then
    \[9+x=9\Rightarrow x=0\]
    \[9+x=18\Rightarrow x=9\]                                                                                                                               
    \[x=27\Rightarrow x=18,\]which is not possible.                                                                                                    
    \[\therefore \] The required value of x = 0 or 9.


adversite


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