SOLUTION: When the natural numbers 1,2,3,....,500 are written, then the digit 3 is used n times in this way.find the value of n ?

Algebra ->  Real-numbers -> SOLUTION: When the natural numbers 1,2,3,....,500 are written, then the digit 3 is used n times in this way.find the value of n ?      Log On


   

Question 1046565: When the natural numbers 1,2,3,....,500 are written, then the digit 3 is used n times in this way.find the value of n ?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
The occurances of the digit 3 are:
3, 13, 23, 30-32, 33, 34-39, 43, 53, 63, 73, 83, 93,
103, 113, 123, 130-132, 133, 134-139, 143, 153, 163, 173, 183, 193,
203. . . . .
303. . . . .
403. . . . . 493
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This is the 1st line repeated 5 times
I count 20 3's in the 1st line
+5%2A20+=+100+
Then I have to add 300 through 399 extra 3's on the 4th line
That's +100+ more 3's
+100+%2B+100+=+200+
+n+=+200+ is my guess
You should get a 2nd opinion on this, however