ASAP please

Let X be the lifetime of an ipad which is known to be exponential with parameter 6' = 6 measured in years. a. f Find the probability that a particular ipad lives more that 4 years. b.;' Knowing that your ipad is 5 years old and still working perfectly, what is the probability that you can use it at least for an additional 4 years? c. 1" What is the expected lifetime and the standard deviation of the lifetime of such an ipad ? d./ If a store has 10 such ipads what is the probability that all of them will be in working condition after 4 years? of Calculate ELK\"). Hint: you need to use the gamma function Mo) = f3\": za'le" six and substitution