SOLUTION: Subjects for the next presidential election poll are contacted using telephone numbers in which the last four digits are randomly selected​ (with replacement). Find the probabili

Algebra.Com
Question 1132477: Subjects for the next presidential election poll are contacted using telephone numbers in which the last four digits are randomly selected​ (with replacement). Find the probability that for one such phone​ number, the last four digits include at least one 0.
The probability is ?
Answer by ikleyn(52776)   (Show Source): You can put this solution on YOUR website!
.

ANSWER.   The probability is    = 0.3439 = 34.39%.


SOLUTION 

  is the number of all possible phone numbers consisting of 4 digits from 0 to 9 inclusively.


  is the number of all possible phone numbers consisting of 4 digits from 1 to 9 inclusively  
     (that do not include  0 (zero) among the 4 digits).


The difference   -  is the number of those 4 digit phone numbers that include at least one 0 (zero).


The ratio    is the probability you are looking for.

Solved,  explained and completed.


RELATED QUESTIONS

Subjects for the next presidential election poll are contacted using telephone numbers in (answered by ikleyn)
I can only remember a seven-digit telephone number if the first three digits (the... (answered by CPhill,ikleyn)
Adam is allowed to choose his own telephone number. The first three digits are set 425-.... (answered by stanbon)
In a certain country, telephone numbers have 9 digits. The first two digits are the area... (answered by Boreal)
In a survey of 1000 eligible voters selected at random, it was found that 200 had a... (answered by stanbon)
In a survey of 1000 eligible voters selected at random, it was found that 100 had a... (answered by stanbon)
In a survey of 1000 eligible voters selected at random, it was found that 200 had a... (answered by Boreal)
In 2014, a certain state added a ninth area code. Using the information about telephone... (answered by ikleyn)
In a small city there are different exchanges possible for each 7-digit telephone number. (answered by josmiceli)