 All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars  perplexus dot info  Match the Numbers (Posted on 2011-04-07) A base ten positive integer is called a Matched Number if each of the respective sod’s in their duodecimal and hexadecimal representations is a prime number, where sod(x) represents the sum of the digits of x.

For example, 73 (base ten) is equal to 61 in the duodecimal system and, 49 in the hexadecimal system. Hence, 73 (base ten) is a Matched Number since each of the sods of 6112 and 4916 considered in their respective bases, is a prime number.

Determine the probability that X is a Matched Number, given that X is a positive integer drawn at random between 100 (base ten) and 9999 (base ten) inclusively.

 Submitted by K Sengupta No Rating Solution: (Hide) The probability is 779/9900. For a detailed explanation, refer to the solution submitted by Charlie in this location. Subject Author Date re: computer solution -- listing continued Charlie 2011-04-07 16:04:26 computer solution Charlie 2011-04-07 16:01:38 Please log in:

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