Exponential Distribution Question

[Caution]

Hi all,
Can anyone teach me this problem ? Thanks

The life of a tiger is exponentially distributed with a mean of 15 years.If a tiger is 10 years old, what is the expected remaining life of the tiger?

A 5 years
B 10 years
C 15 years
D Longer than 15 years

 

[StoneTemplePython]

Can you tell me your understanding of 'memorylessness'? What distributions have this property and what does it mean?

 

[Caution]

Can you tell me your understanding of 'memorylessness'? What distributions have this property and what does it mean?

It means the probability distribution of the remaining time until the event occurs always is the same, regardless of how much time (s) already has passed. So I'm guessing the answer is 5?

 

[StoneTemplePython]

It means the probability distribution of the remaining time until the event occurs always is the same, regardless of how much time (s) already has passed. So I'm guessing the answer is 5?

so if the probability distribution is the same whether 0 years have passed or 7 years have passed, then what does that tell you about forward looking expectations?

Also do you know which distributions exhibit memorylessness? (There are only 2...)