Answer:
The original selling price would be $ 515.87 ( approx )
Step-by-step explanation:
Let x be the original selling price ( in dollars ),
After marking down 10%,
New selling price = x - 10% of x = x - 0.1x = 0.9x
Again after marking down 30%,
Final selling price = 0.9x - 30% of 0.9x
= 0.9x - 0.3 × 0.9x
= 0.9x - 0.27x
= 0.63x
According to the question,
0.63x = 325

Hence, the original selling price would be $ 515.87.
The equivalent ratio of 9:25 is 36:100.
Ratio expresses the degree of proportionality between two or more numbers. It expresses the number of times one number is contained in another number.
In order to make the ratios equal, the relationship that exists between 9 and 36 has to be determined. 36 is a multiple of 9. It is 9 multiplied by 4. So, in order to make the ratios equal, multiply, 25 by 4.
25 x 4 = 100
To learn more about ratios, please check: brainly.com/question/17995727
Answer:
4.27%
Step-by-step explanation:
We have been given that college students average 8.6 hours of sleep per night with a standard deviation of 35 minutes. We are asked to find the probability of college students that sleep for more than 9.6 hours.
We will use z-score formula to solve our given problem.

z = z-score,
x = Random sample score,
= Mean,
= Standard deviation.
Before substituting our given values in z-score formula, we need to convert 35 minutes to hours.




Now, we need to find
.
Using formula
, we will get:

Using normal distribution table, we will get:



Therefore, 4.27% of college students sleep for more than 9.6 hours.
For this case we must find the product of the following expression:

We combine using the product rule for radicals:
![\sqrt [n] {a} * \sqrt [n] {b} = \sqrt [n] {ab}](https://tex.z-dn.net/?f=%5Csqrt%20%5Bn%5D%20%7Ba%7D%20%2A%20%5Csqrt%20%5Bn%5D%20%7Bb%7D%20%3D%20%5Csqrt%20%5Bn%5D%20%7Bab%7D)
So, we have:

We rewrite the 216 as

By definition of properties of powers and roots we have:
![\sqrt [n] {a ^ n} = a ^ {\frac {n} {n}} = a](https://tex.z-dn.net/?f=%5Csqrt%20%5Bn%5D%20%7Ba%20%5E%20n%7D%20%3D%20a%20%5E%20%7B%5Cfrac%20%7Bn%7D%20%7Bn%7D%7D%20%3D%20a)
Then, the expression is:

Answer:
Option D