Answer:
First do the case in which none of the digits is 0.
There are 9 ways to choose the digit that repeats 3 times and 8 ways to pick the other, after this there are 4 ways to order the digits. So 9×8×4.
Now we look at the cases in which the digit 0 repeats 3 times. Clearly the 9 numbers are 1000,2000,3000,…,9000.
Lastly we look at the cases in which 0 appears once. There are 9 ways to pick the other digit and 3 ways to order.
So the final answer is 9×8×4+9+9×3.
Answer:
f(2) = g(2) and f(0) = g(0)
Step-by-step explanation:
When x = x in f(x) and g(x), that means the two functions are equal.
Answer:
And we can find this probability with the following difference and using the normal standard table or excel we have:
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem
Let X the random variable that represent the variable of interest of a population, and for this case we know the distribution for X is given by:
Where
and
We are interested on this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability with the following difference and using the normal standard table or excel we have: