One day, Lee decides to write down the numbers 1.....999
Lee chooses one of the digits written down at random. What is the probability that Lee chooses a 7?
i think this means it's asking for the number of 7 digits from 1....999
+36916 Not sure about that answer
I count up in my head 300 7's
out of 2889 digits (see previous answer)
300/2889 =100/963
+118609
One day, Lee decides to write down the numbers 1.....999
How many times does 7 appear.
Lets see.
Units
Each decade 7 apears once. 100 decades so that is 100 times
Place value 10
Each century seven appears 10 times, 10 centuries so that is 100 sevens
Place value 100
Each millenium seven appears 100 times
So I get 300 times. You got 297. Who is wrong?
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If 7 appears 300 times it stands to reason that so do 1,2,3,4,5,6,8, and 9 do too.
How about 0
units first decade not at all so that is 99 times
tens first century not at all so that is 90 times
hundreds first milenium not at all so that is 0 times
So zero appears 189 times I think
300*9+189=2889 digits altogether.
so I get 300/2889 Same as EP.
I could easily have miscounted.
