Answer Happy

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right please thank you!!! Mostly just C!!!
The lifetime of a certain brand of battery is normally
distributed with a mean value of 11 hr and a standard deviation of
0.8 hr when it is used in a particular DVD player. Suppose that two
new batteries are independently selected and put into the player.
The player stops functioning as soon as one of the batteries fails.
(Round your answers to four decimal places.)
(a)
What is the probability that the player functions for at least 9
hr? *** Answer is
0.9938******
____________________
(b)
What is the probability that the DVD player works for at most 12
hr? ***THE ANSWER IS 0.9938***
____________________
(c)
Find a number c* such that only 10% of all DVD players
will function without battery replacement for more
than c* hours. ***
The answer isn't 11.83 or 12.024, it is marking it
wrong***
c* = ____________ hr
THE ANSWER IS NOT 11.83 OR 12.024 IT IS MARKING IT
WRONG, PLEASE DON'T WRITE THE WRONG ANSWER!!!!!!