947 because the negative signs in both the numbers get crossed out and become a plus. So in that case, you would do 58+889 which is 947.
The formula is
time = (Worker 1 * Worker 2) / (Worker 1 + Worker 2)
time = (18 * 20) / (18 + 20)
time = 360 / 38
time =
<span>
<span>
<span>
9.4736842105
</span>
</span>
</span>
minutes
So, the answer is "a. 9.5 minutes".
Source
http://www.1728.org/work.htm
Answer:

Step-by-step explanation:
Given that:
Little Gull Island Lighthouse shines a light from a height of 91 feet above the sea level.
The angle of depression is unknown.
Distance of the point at sea surface from the base of lighthouse is 865 ft.
This situation can be modeled or can be represented as the figure attached in the answer area.
The situation can be represented by a right angled
in which we are given the base and the height of the triangle.
And we have to find the value of
(Because they are the internal vertically opposite angles).
Using tangent ratio:


Therefore, the angle of depression is: 
Answer:
Step-by-step explanation:
- 5x² - 20x + 15 = 0
- x² - 4x + 3 = 0
- x² - 4x + 4 = 1
- (x - 2)² = 1
- √(x - 2)² = √1
- x - 2 = ± 1
- x = 2 ± 1
- x = 1, x = 3