10000 digits can be used for 4 digit A.T.M code.
<u>Solution:</u>
Given that A.T.M required 4 digit codes using the digits 0 to 9.
Need to determine how many four digit code can be used.
We are assuming that number starting with 0 are also valid ATM codes that means 0789 , 0089 , 0006 and 0000 are also valid A.T.M codes.
Now we have four places to be filled by 0 to 9 that is 10 numbers
Also need to keep in mind that repetition is allowed in this case means if 9 is selected at thousands place than also it is available for hundreds, ones or tens place .
First digit can be selected in 10 ways that is from 0 to 9.
After selecting first digit, second digit can be selected in 10 ways that is 0 to 9 and same holds true for third and fourth digit.
So number of ways in which four digit number is created = 10 x 10 x 10 x 10 = 10000 ways
Hence 10000 digits can be used for 4 digit A.T.M code.
Answer:
observational study
Step-by-step explanation:
This situation calls for an observational study. Unfortunately, cardiovascular health is difficult to measure unless one defines some "health scale" so that health could be roughly quantitized.
Area of the shaded region = area of big square minus area of little square.
Here is the set up:
Let A_s = area of shaded region.
A_s = (2x + 2)(3x - 4) - [(x - 3)(x - 6)]
Take it from here.
Answer: A. 664
Step-by-step explanation:
Given : A marketing firm is asked to estimate the percent of existing customers who would purchase a "digital upgrade" to their basic cable TV service.
But there is no information regarding the population proportion is mentioned.
Formula to find the samples size , if the prior estimate to the population proportion is unknown :
, where E = Margin of error.
z* = Two -tailed critical z-value
We know that critical value for 99% confidence interval = 
[By z-table]
Margin of error = 0.05
Then, the minimum sample size would become :
Simplify,
Thus, the required sample size= 664
Hence, the correct answer is A. 664.
