Answer:
a) 50.34% probability that the arrival time between customers will be 7 minutes or less.
b) 24.42% probability that the arrival time between customers will be between 3 and 7 minutes
Step-by-step explanation:
Exponential distribution:
The exponential probability distribution, with mean m, is described by the following equation:

In which
is the decay parameter.
The probability that x is lower or equal to a is given by:

Which has the following solution:

The probability of finding a value higher than x is:

Mean of 10 minutes:
This means that 
A. What is the probability that the arrival time between customers will be 7 minutes or less?


50.34% probability that the arrival time between customers will be 7 minutes or less.
B. What is the probability that the arrival time between customers will be between 3 and 7 minutes?





24.42% probability that the arrival time between customers will be between 3 and 7 minutes
It's dependent on the context. A book may ask you to find the f'(x) of a function and you may have to use a u sub in your problem which requires you to find the dy/dx of what you substitute. So in this case both would be used.
Answer:
x = -36, y = 6, z = -6
Step-by-step explanation:
The requirement x/z = -z means x = -z².
The requirement x/y = z means x = yz.
These two requirements together mean yz = -z², or y = -z.
The requirements that z/2 and z/3 are integers mean that z is a multiple of 2·3 = 6. The smallest magnitude non-zero multiple is z=-6 (since we also require z < -z).
Using z=-6, we have x = -z² = -36; y = -(-6) = 6.
For some positive integer n, ...
... x = -36n², y = 6n, z = -6n.
Ten to third power is 1,000 :)