Answer:
The probability that the child must wait between 6 and 9 minutes on the bus stop on a given morning is 0.148.
Step-by-step explanation:
Let the random variable <em>X</em> represent the time a child spends waiting at for the bus as a school bus stop.
The random variable <em>X</em> is exponentially distributed with mean 7 minutes.
Then the parameter of the distribution is,
.
The probability density function of <em>X</em> is:
Compute the probability that the child must wait between 6 and 9 minutes on the bus stop on a given morning as follows:
![=\int\limits^{9}_{6} {\frac{1}{7}\cdot e^{-\frac{1}{7} \cdot x}} \, dx \\\\=\frac{1}{7}\cdot \int\limits^{9}_{6} {e^{-\frac{1}{7} \cdot x}} \, dx \\\\=[-e^{-\frac{1}{7} \cdot x}]^{9}_{6}\\\\=e^{-\frac{1}{7} \cdot 6}-e^{-\frac{1}{7} \cdot 9}\\\\=0.424373-0.276453\\\\=0.14792\\\\\approx 0.148](https://tex.z-dn.net/?f=%3D%5Cint%5Climits%5E%7B9%7D_%7B6%7D%20%7B%5Cfrac%7B1%7D%7B7%7D%5Ccdot%20e%5E%7B-%5Cfrac%7B1%7D%7B7%7D%20%5Ccdot%20x%7D%7D%20%5C%2C%20dx%20%5C%5C%5C%5C%3D%5Cfrac%7B1%7D%7B7%7D%5Ccdot%20%5Cint%5Climits%5E%7B9%7D_%7B6%7D%20%7Be%5E%7B-%5Cfrac%7B1%7D%7B7%7D%20%5Ccdot%20x%7D%7D%20%5C%2C%20dx%20%5C%5C%5C%5C%3D%5B-e%5E%7B-%5Cfrac%7B1%7D%7B7%7D%20%5Ccdot%20x%7D%5D%5E%7B9%7D_%7B6%7D%5C%5C%5C%5C%3De%5E%7B-%5Cfrac%7B1%7D%7B7%7D%20%5Ccdot%206%7D-e%5E%7B-%5Cfrac%7B1%7D%7B7%7D%20%5Ccdot%209%7D%5C%5C%5C%5C%3D0.424373-0.276453%5C%5C%5C%5C%3D0.14792%5C%5C%5C%5C%5Capprox%200.148)
Thus, the probability that the child must wait between 6 and 9 minutes on the bus stop on a given morning is 0.148.
Step-by-step explanation:
Answer:
x = 10
Step-by-step explanation:
Using the rules of logarithms
• log x + log y ⇔ log(xy)
• log
⇔ n log x
• log x = log y ⇒ x = y
Given
ln20 + ln5 = 2 lnx , then
ln(20 × 5) = ln
ln 100 = ln, hence
x² = 100 ( take the square root of both sides )
x = 10
Answer:
1
Step-by-step explanation:
The denominator in 9 is one. This also applies for all numbers without a denominator.
Hope this helps :)
Answer:
A.) 15.60=11.40+10x
Step-by-step explanation:
okay we know kathy spent 15.60 in total at the post office
so we know 15.60 will be after the equal sign.
she paid 11.40 only on the package
and rest of money was on stamps.
15.60-11.40= 4.20
so she used 4 dollars and 20 cents for stamps if she bought 10 we need to divied 4.20/10=0.42
0.42 cents for each stamps so we need a equation that will give us this answer.
Me i go thru each one and solve for x
lucky for me i just need to solve one
because equation A solves it correctly.
15.60=11.40+10x
subtract 11.40 on both sides
15.60-11.40
4.20=10x
now we divide 10 on each side
4.20/10=0.42
x=0.42
