the second one, and the third one
Answer:
answer = 12.87 km/h
Step-by-step explanation:
Given
Ship A is sailing east at 25 km/h = 
ship B is sailing north at 20 km/h =
here x and y are the sailing at t = 4 : 00 pm for ship A and B respectively
so we get x = 4 ×25 =100 km/h
y = 4× 20 = 80 km/h
let z is the distance between the ships, we need to find
at t = 4 hr
At noon, ship A is 130 km west of ship B (12:00 pm)
so equation will be


derivative first equation w . r. to t we get



![\frac{dz}{dt} =\frac{1}{z}[(x -130)\frac{dx}{dt} +y\frac{dy}{dt}]](https://tex.z-dn.net/?f=%5Cfrac%7Bdz%7D%7Bdt%7D%20%3D%5Cfrac%7B1%7D%7Bz%7D%5B%28x%20-130%29%5Cfrac%7Bdx%7D%7Bdt%7D%20%2By%5Cfrac%7Bdy%7D%7Bdt%7D%5D)


<span>[2×(10+5)]-5
[2*15]-5
30-5
25</span>
This is 2.5 standard deviations from the mean.
We find this by subtracting the mean from our value, and dividing by the standard deviation:
(63-38)/10 = 25/10 = 2.5