Statistics Question

Nissan guarantees that the eNVZO Lithium-ion battery used in the Nissan Leaf will have a battery capacity of greater than 75% for the first 160,000 km of driving. Once the battery capacity is less than ?5%, it is described as failed. Assuming that the battery life follows a normal distribution, ,u = 160,000 km and o = 17,000 km , determine: a] The probability that a battery will last I. Exactly 160,000 km. N. More than 185,000 km. b] The probability that a random sample of 10 batteries will last more than 185,000 km c} The km's by which 40% of batteries will have failed