During the holiday season, the number of letters a post office received per day had an approximately normal distribution with a mean of 20,000 and a standard deviation of 400. What proportion of days have more than 20,500 letters?

b.-4 units

all you   do is count how many times you move

first, you divide the triangle in two, tô form a retangle triangle. after, using pythagoream theorem:

18^2 = 14^2 + (x/2)^2

(x^2/4) + 196 = 324

x^2/4 = 324 - 196

x^2/4 = 128

x^2 = 512

x = √512

x = √2^9

x = 16√2 cm

i hope i you.

6

step-by-step explanation:

the answer is a) y= 2 csc [0.5 (x+pi/2)]-1

step-by-step explanation: