Answer:
a) 
b) 
Step-by-step explanation:
Previous concepts
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 "life lengths of automobile tires of a certain brand" and we know that the distribution is given by:

The cumulative distribution function is given by:

Part a
We want to find this probability:
and for this case we can use the cumulative distribution function to find it like this:

Part b
For this case w want to find this probability

We have an important property on the exponential distribution called "Memoryless" property and says this:
On this case if we use this property we have this:
We can use the definition of the density function and find this probability:

Answer:
C = 60pi cm or approximately 188.4 cm
Step-by-step explanation:
The circumference of a circle is given by
C = 2 * pi *r
C = 2* pi * 30
C = 60 pi
We can approximate pi by 3.14
C is approximately 60*3.14 or 188.4
Answer:
c = 17 Km
Step-by-step explanation:
Using Pythagoras' identity in the right triangle.
The square on the hypotenuse is equal to the sum of the squares on the other 2 sides , that is
c² = 8² + 15² = 64 + 225 = 289 ( take square root of both sides )
c =
= 17 Km
Idk if I can simplify that
Answer:
The answer is: both class have the same ratio.
Step-by-step explanation:
Get the ratio of tall to short. Divide Tall by Short:
Jack's class:
18/10 = 1.8 tall one for every short one
Michael's class:
54/30 = 1.8
The ratio is the same!
You can further prove this by multiplying 18 times 3 and getting 54, and 10 times 3 and getting 30.
Hope this Helps!! Have an Awesome Day!! (-: