Answer:

And we can find the individual probabilities like this:
And adding we got:

Step-by-step explanation:
Previous concepts
The binomial distribution is a "DISCRETE probability distribution that summarizes the probability that a value will take one of two independent values under a given set of parameters. The assumptions for the binomial distribution are that there is only one outcome for each trial, each trial has the same probability of success, and each trial is mutually exclusive, or independent of each other".
Let X the random variable of interest, on this case we now that:
The probability mass function for the Binomial distribution is given as:
Where (nCx) means combinatory and it's given by this formula:
Solution to the problem
For this case we want to find this probability:

And we can find the individual probabilities like this:
And adding we got:

We can convert 20km to 20,000m. Then, we can subtract 800m (walking distance) from 20,000m which would result in 19,200m. Then we can put 19,200m and 20,000m as a fraction (19200/20000). Before we can multiply it by 100 to make it in the percentage form, we can get rid of 2 zeroes for both number making it 192/200 and then further simplifying it to 24/25 by dividing both numbers by 8. Finally to get the percentage we can multiply 24 and 100 (2400) and then divide the result (2400) by 25. The final answer is 2400/25=96 meaning he cycled 96% of the journey and walked 4% of the journey (100-96=4).
The ratios of sin x° and cos y° are 15/8.
We have given that,
Use the image below to answer the following question.
We have to determine to find the value of sin x° and cos y°.
By applying Pythagoras theorem in the triangle given in the picture,
<h3>What is
the Pythagoras theorem?</h3>
(Hypotenuse)² = (leg 1)² + (leg 2)²
PO² = (15)² + 8²
PO² = 225 + 64
PO = √289
PO = 17
By applying the sine rule in the given triangle,
sin(x°) = Opposie side/hypotenous
= 15/17
cos(y°) = Adjucent side/hypotenous
= 8/17
The relation between the ratio of sin(x) and cos(x) will be,


Therefore the ratios of sin x° and cos y° are 15/8.
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Answer:
it might be the second one not sure
Answer:
The value of x that gives the maximum transmission is 1/√e ≅0.607
Step-by-step explanation:
Lets call f the rate function f. Note that f(x) = k * x^2ln(1/x), where k is a positive constant (this is because f is proportional to the other expression). In order to compute the maximum of f in (0,1), we derivate f, using the product rule.

We need to equalize f' to 0
- k*(2x ln(1/x) - x) = 0 -------- We send k dividing to the other side
- 2x ln(1/x) - x = 0 -------- Now we take the x and move it to the other side
- 2x ln(1/x) = x -- Now, we send 2x dividing (note that x>0, so we can divide)
- ln(1/x) = x/2x = 1/2 ------- we send the natural logarithm as exp
- 1/x = e^(1/2)
- x = 1/e^(1/2) = 1/√e ≅ 0.607
Thus, the value of x that gives the maximum transmission is 1/√e.