Step-by-step explanation:

• y2 → -1
• y1 → 5
• x1 → 4
• x2 → -3

Answer:
12
Step-by-step explanation:
Given:
On every 3 DVDs she rents, 1 DVD is received for free
Rent of each DVD = $3
Total amount paid = $114
Now,
The total number of DVDs she took on rent =
or
The total number of DVDs she took on rent =
or
The total number of DVDs she took on rent = 38
also,
For every 3 DVDs she gets 1 Free DVD
thus,
For every 1 DVD she gets
free DVD
therefore,
For 38 DVD she gets
free DVD
or
she gets 12.67 DVDs free
Since,
the DVDs cannot be given in fraction
Hence she will get 12 free DVDs
The exponential distribution is:

where

The probability we want is how likely will a dvd player last more than 8 years, given it has already lasted 5 years
To find this, you use conditional probability.

where A is P(x>8) and B is P(x>5)
To find these probabilities, integrate over the distribution:

Sub into conditional probability formula:

Final Answer: Given a dvd player is more than 5 years old, the probability that it will last another 3 more years is about 54.9%