Answer:
30.8 I believe is your answer
Step-by-step explanation:
Answer:
Barbara's speed in clear weather is
and in the thunderstorm is
.
Step-by-step explanation:
Let
be the speed and
be the time Barbara drives in clear weather, and let
be the speed and
be the time she drives in the thunderstorm.
Barbara drives 22 mph lower in the thunderstorm than in the clear weather; therefore,
(1). 
Also,
(2).
(3).
,
and
(4). 
From equations (2) and (3) we get:


putting these in equation (4) we get:

and substituting for
from equation (1) we get:

This equation can be rewritten as

which has solutions


We take the first solution
because it gives a positive value for 


.
Thus, Barbara's speed in clear weather is
and in the thunderstorm is
.
27/36 = n/4
27*4 = 36n
108 = 36n
108/36 = 36n/36
n = 3
According to the Pythagorean theorem, the square of the hypotenuse (the longest side) of a right-angled triangle equals to the sum of the squares of the other two sides. In this case, the ladder is the hypotenuse, which equals to the distance between the bottom of the ladder and the tree + the distance we want to find (x):
5² + x² = 13²
25 + x² = 169
x² = 144
x = √144 = 12.
The distance between the ground and the top of the ladder is 12 ft.