Records suggest that the normal distribution with mean 50 and standard deviation 9 is a plausible model

Question:

Records suggest that the normal with mean 50 and standard deviation 9 is a plausible model for a measurement of the amount of suspended solids (ppm) in river water. Find
(a) P[X < 46.4]
(b) P[X < 57.2]
(c) P[X > 57.2]
(d) P[X > 60.8]
(e) P[33.8 < X < 64.4]
(f) P[52.5 < X < 60.9] Distribution
The word "distribution" has several meanings in the financial world, most of them pertaining to the payment of assets from a fund, account, or individual security to an investor or beneficiary. Retirement account distributions are among the most...