+0  
 
0
13
1
avatar+1211 

Sam writes down the numbers $1,$ $2,$ $\dots,$ $315,$ $316,$ $317,$ $\dots,$ $249,$ $250.$

(a) How many digits did Sam write, in total?

(b) Sam chooses one of the digits written down at random.  What is the probability that Sam chooses a $2$?

 Mar 10, 2024
 #1
avatar+128794 
+1

1-9  = 9 digits

10 - 99 = 180 digits

100 - 199 = 300 digits

200 - 250  = 151 digits

9 + 180 + 300 + 151 =     640 digits

 

No. of 2's

1-100  =  10 + 10  = 20

101 - 199 = 10 + 10  = 20

200 - 250  = 5 + 10 + 51  = 66

20 + 20 + 66  =  106

Prob of 2  =   106  / 640 =  53 /  320    (if I didn't mis-count !!! )

 

cool cool cool

 Mar 10, 2024
edited by CPhill  Mar 10, 2024
edited by CPhill  Mar 10, 2024

8 Online Users

avatar
avatar
avatar
avatar
avatar
avatar