20
Step-by-step explanation:
Step 1:
Let the number be 50 and to find 40% of 50 is given interms of expression as follows
To express the percentage the following strategy is used
Eg: 40% = 
∴ To express 40% of 50 is

Step 2:
On simplification the above expression we could get

= 20
Recall that the mean of a given set of numbers is the sum of the numbers divided by the number of numbers, therefore, the mean of the dataset is:

Now, the range of a data set is the difference between the maximum and the minimum, in this case, the maximum is 99, and the minimum is 15 therefore, the range is:

Finally, the standard deviation is given by the following formula:

where N is the sample size, x_i is an element of the set, and x^- is the mean. The standard deviation of the set is:

<h2>Answer: </h2>
The value of x is 
Explanation:
The expression is
Adding
to both sides of the equation, we get,

Using log definition, if
then
, we have,

Using exponent rule,
,

Simplifying, we have,

Dividing both sides by 9, we have,

Simplifying,

Thus, the value of x is 
No problem the answer is 34w i thinks o but make hru look like it