Find the probability without using excel function.

An automobile manufacturer is concerned about a fault in the braking mechanism of a particular model. The fault can, on rare occasions, cause a catastrophe at high speed. The distribution of the number of cars per year that will experience the catastrophe is a random variable with variance = 5.

1. What is the probability that at most a total of 30 cars in 35 years will experience a catastrophe?
2. What is the probability that an average of fewer than 3 cars in 35 years will experience a catastrophe?

find the value without using excel function.