(QUESTION TWO) Can I have help with this, please?

The lifetime of a Zebra brand motorcycle is observed to ollow a normal distribution with mean u = 5 years and the standard deviation 0 = 0.81 years. The motorcycle company has decided to replace any motorcycle that fails during the guaranteed period. How long the guaranteed period should be if the company wishes to replace no more than 11% of the motorcycle? Set a random variable x that represents the lifetime of a Zebra brand motorcycle (in years}