Suppose that the amount of time (in months) that a light bulb lasts be

Suppose that the amount of time (in months) that a light bulb lasts be

Suppose that the amount of time (in months) that a light bulb lasts before it burns out hasan exponential distribution with parameter ? = 1/4.a) What is the probability that it lasts at least three months?b) If it has already lasted two months, what is the probability that it will last at least threemore months?c) On average, how many months will the light bulb last?