+0  
 
0
46
3
avatar

One day, River writes down the numbers \(1, 2, \dots, 999.\) River chooses one of the digits written down at random. What is the probability that River chooses a 7?

 May 3, 2020
edited by Guest  May 3, 2020
 #1
avatar
0

Please fix the LaTeX.

 May 3, 2020
 #2
avatar
0

189 , 300 , 300 , 300 , 300 , 300 , 300 , 300 , 300 , 300 >>Total = 2889

 

As you can see, there 300 7 between 1 and 999, counting duplicates such as 177, 777.....etc. The total of all digits from 1 to 999 =2,889.

Therefore, the probability is =300 / 2889 =100 / 963

 May 3, 2020
 #3
avatar+50 
0

This is from the AoPs intro to counting and probability class...

 

WE ARE NOT HERE TO DO YOUR WORK FOR YOU...

 May 4, 2020

24 Online Users

avatar