Page 2 - 16.2 CH-16-LESSON NOTE(DIVISIBILITY)
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ANSWER :
                  Since 21y5is a multiple of 9.
                 Therefore according to the divisibility rule of 9, the sum of all the digits
                 should be a multiple of 9.






               Since 21y5 is a multiple of 9.


                Example- 2

                   2. If 31z5 is a multiple of 9, where z is a digit, what is the value of z?
                   You will find that there are two answers for the last problem. Why
                   is this so?
                   ANSWER :
                        Since 31z5 is a multiple of 9.
                       Therefore according to the divisibility rule of 9, the sum of all thedigits
                       should be a multiple of 9.







                       If





                       Hence 0 and 9 are two possible answers.





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