Can someone help with this please
2 answers:
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Answer:
<em>Roberto's speed in still water is 6 miles/hour and the river speed is 2 miles/hour</em>
Step-by-step explanation:
<u>Relative Speed</u>
When a body is moving at a constant speed v, the distance traveled in a time t is:
When Roberto rows downstream, his speed in still water is added to the speed of the water, making it easier to travel the required distance.
When Roberto rows upstream, his speed in still water is affected by the speed of the water, both are subtracted and the required distance is covered in more time.
Let's call
x = Roberto's rowing speed in still water
y = Speed of the river current
The speed when rowing downstream is x+y, thus the distance traveled is
Where t1=2.5 hours. Substituting values:
Rearranging, we find the downstream equation:
The speed when rowing upstream is x-y, and the distance traveled is
Where t2=5 hours. Substituting values:
Rearranging, we find the upstream equation:
Multiplying [1] by 2:
Adding this equation to [2]:
Solving:
Dividing [2] by 5:
Solving for y
Thus, Roberto's speed in still water is 6 miles/hour and the river speed is 2 miles/hour
Answers and Step-by-step explanations:
1. We need to plug in values of x into the functions f(x) and g(x):
f(2) = 2.5 * 2 - 10.5 = -5.5 g(2) = = 16
f(3) = 2.5 * 3 - 10.5 = -3 g(3) = = 8
f(4) = 2.5 * 4 - 10.5 = -0.5 g(4) = = 4
f(5) = 2.5 * 5 - 10.5 = 2 g(5) = = 2
f(6) = 2.5 * 6 - 10.5 = 4.5 g(6) = = 1
2.
(a) Notice that at 14 on the x-axis, the blue line is above 4. Meanwhile, at 14, the red line is less than 2. Obviously, we can see that if the printed ad revenue was less than 2 and the online ad revenue was greater than 4, that's more than a double, so the lead marketing executive is correct.
(b) The approximate year that the revenues were equal is the place where the lines intersect. It's approximately at Year 7.5.
3.
(a) The Western Beach is clearly decreasing; it is decreasing by 2 ft per year. Meanwhile, the Dunes Beach is clearly increasing; it's increasing by 5 ft per year. (I'm not sure what kinds of "patterns" you're looking for).
(b) Year 11 and 12; this is because here, Western is going from 78 to 76 ft and Dunes is going from 75 to 80, so they'll likely coincide sometime in that time interval.
(c) One thing you can do is to create equations (of the form y = mx + b) for each of the beaches and then set those linear equations equal to each other.