Adult salmon have lengths that are normally distributed with a mean of = 70 cm and

Question:

Adult salmon have lengths that are normally distributed with a mean of μ = 70 cm and a standard deviation of σ = 5.4 cm.
(a) What is the probability that an adult salmon is longer than 80 cm?
(b) What is the probability that an adult salmon is shorter than 55 cm?
(c) What is the probability that an adult salmon is between 65 and 78 cm long?
(d) What is the value of c for which there is a 95% probability that an adult salmon has a length within the interval [70 - c, 70 + c]?