Answer:
15 ft
Step-by-step explanation:
This problem can be represented by a right angle triangle, shown in the diagram below.
The distance between Jin and Zoe is the hypotenuse of the triangle, x.
According to Pythagoras theorem,
hyp² = opp² + adj²
Where opp is the opposite side and adjacent is the adjacent side to any angle of consideration (which is not important in this case)
Hence:
x² = 12² + 9²
x² = 144 + 81
x² = 225
Finding the square root:
x = 15 ft
Jin and Zoe are 15 ft apart.
The probability of picking one girl would be . That is because there are 5 girls out of the 12 students, and the probability of an event occuring is:
.
Using that same logic, the next student should be easier. We reduced the student population by 1, so we have 11 possible ways it can happen now instead of 12, so that gives us:, for the probability of picking a boy as the second pick.
And lastly, using the same logic shown above, the probability of picking a girl on the third pick would be:.
We are not done, though. We have the separate probabilities, but now we have to multiply then together to figure out the probability of this exact event happening:
Which when reduced is:
Answer:
Step-by-step explanation:
Previous concepts
The central limit theorem states that "if we have a population with mean μ and standard deviation σ and take sufficiently large random samples from the population with replacement, then the distribution of the sample means will be approximately normally distributed. This will hold true regardless of whether the source population is normal or skewed, provided the sample size is sufficiently large".
The exponential distribution is "the probability distribution of the time between events in a Poisson process (a process in which events occur continuously and independently at a constant average rate). It is a particular case of the gamma distribution". The probability density function is given by:
And 0 for other case. Let X the random variable that represent "The number of years a radio functions" and we know that the distribution is given by:
Or equivalently:
Solution to the problem
For this case we are interested in the total T, and we can find the mean and deviation for this like this:
If we solve for T we got:
And the expected value is given by:
And we can find the variance like this:
And then the deviation is given by:
And the distribution for the total is:
And we want to find this probability:
And we can use the z score formula given by:
And replacing we got this: