Draw the density curve corresponding to each of the following normal random variables, and then shade the area corresponding to the desired probability. You do not need to compute the probability.
a. X is a normal random variable with μ = 75 and σ = 5, P(70 ≤ X ≤ 85).
b. X is a normal random variable with μ = 15 and σ = 10, P(5 ≤ X ≤ 20).
c. X is a normal random variable with μ = 100 and σ = 15, P(X > 115).