Answer:
r = 225 Mil/h speed of the airplane in still air
Step-by-step explanation:
Then:
d is traveled distance and r the speed of the airplane in still air
so the first equation is for a 4 hours trip
as d = v*t
d = 4 * ( r + 25) (1) the speed of tail wind (25 mil/h)
Second equation the trip back in 5 hours
d = 5 * ( r - 25 ) (2)
So we got a system of two equation and two unknown variables d and
r
We solve it by subtitution
from equation (1) d = 4r + 100
plugging in equation 2
4r + 100 = 5r - 125 ⇒ -r = -225 ⇒ r = 225 Mil/h
And distance is :
d = 4*r + 100 ⇒ d = 4 * ( 225) + 100
d = 900 + 100
d = 1000 miles
mu = 1100 = population mean
sigma = 275 = population standard deviation
x = 1400 = raw score
z = z score
z = (x-mu)/sigma
z = (1400-1100)/(275)
z = 300/275
z = 1.0909090909091 approximately
z = 1.09
Convention is to round to two decimal places so that you can use a Z table to look up the area under the curve (which helps determine probability).
The positive z score is due to Paula's raw score being above the mean.
For (-7,3) and (5,3) the answer is 12. You add the different points, -7 and 5 because one is negative and one is positive. You do not add 3 and 3 because they are the same.
(3,-6) and (3,-10) = 4 because -6 and -10 are negatives. The answer is always positive.
(8,0) and (8,-8) = 8.
6yd and 216in and both equal
