The numbers are determined by A, C, E and G, and any digits can be used in these four positions except that A cannot be zero in the range given.
There are 9 choices for A and 10 each for C, E and G, for a total of 9000 possibilities out of the 9999999 - 999999 = 9,000,000.
The probability is 9,000 / 9,000,000 = 1/1000.
Done this way it seems like a D2.
Another way of figuring it:
B has 1 chance in 10 of satisfying the condition, as does D, and the same for F. Multiplied together that's 1/1000.
Now it seems like a D1.
Posted by Charlie
on 2011-03-09 15:10:32