Yes 900 3 digit numbers
1000/11 = 90.9
round down to 90
9 of those are less than 100
so 81 are between 100 and 999
so that is
P(that a 3 digit number is divisable by 11 ) = 81/900 = 9/100 = 9%
Just as guest said.
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You rounded up instead of down so
instead of ending with the las multiple of 11 LOWER than 1000,
you ended with the first multiple of 11 AFTER 1000.
Oh, I do not like your 900/11 bit either. That could also have put the answer out by a little bit.
In this case it makes no answer difference but sometimes it would. Another thing for you to think about.