-3(2x-3)<3
(-3(2x-3))(-1)<3(-1)
3(2x-3)>-3
(3(2x-3))/3>-3/3
2x-3>-1
2x-3+3>-1+3
2x>2
2x/2>2/2
x>1
Answer:

Step-by-step explanation:
Let the office charge = x
Amount paid by Medicare = ⅞x
Amount paid by Ross = ¼(⅞x) = $262.50
Solve for x

Check:

OK.
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:

I hope this helps you
9=n.n
3.3=n.n
n=3