25 that how much she will need
Answer:
68% of these phones last 3.87 years.
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:

The average lifetime of a certain new cell phone is 3.4 years.
This means that 
So

68% of these phones last how long (in years)?
This is x for which:


Then






68% of these phones last 3.87 years.
I don't see a picture, sorry...
Answers:
Slope = 1.25
y intercept = 4
Explanation:
The slope is the rate of change. In this case, it's the price of getting an extra box.
The y intercept is the starting cost assuming that everyone has to get at least one small box of candy.