find the sum of all natural nos. between 100 and 999,which are multiples of 9.

Asked by riyaliz | 22nd Jul, 2008, 09:58: PM

Expert Answer:

 The sum of natural  numbers between100  and  999  , which are multiplesof 9  are 108 , 117 ,      ,,,,,........... 999

 the number of terms =   108 + ( n - 1) x9 = 999

                                           108  + 9n -9  = 999

                                            99 + 9n  = 999

                                                   n = 100

            the sum of all numbers  =  100 / 2   [  2 x 108  + (  99  x  9 )  ]

                                                             50  [ 216  + 891 ]  = 55350

Answered by  | 25th Jul, 2008, 08:23: PM

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