If the current in a stream moves at a rate of 7 mph. If a boat travels 98 miles downstream in the same time that it takes to travel 49 miles upstream then the speed of the boat in still water is 21 miles per hour.
<h3>What is speed?</h3>
Speed is the distance covered by an object in a certain time period. It is also known as velocity. The formula of speed is as follows:
Speed=Distance/ Time.
<h3>How to calculate speed?</h3>
We have been given that the speed of stream is 7miles per hour.
Let v be the speed of the boat, and t the time to travel
98=t*(7+v) (1)
49=t(v-7) (2)
(1)+(2) => 2tv=147
7t+(49+7t)=98
14t+49=98
14t=49
t=49/14
t=7/2
Put the value of t in equation 1 to get the value of v:
98=t(7+v)
98=7/2(7+v)
196/7=7+v
28=7+v
v=28-7
v=21
Hence if the current in a stream moves at a rate of 7 mph. If a boat travels 98 miles downstream in the same time that it takes to travel 49 miles upstream then the speed of the boat in still water is 21 miles per hour.
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Answer:
0
Step-by-step explanation:
9-9/9--8
0/17
0
Using relations in a right triangle, it is found that the angle of depression is of θ = 56.31º.
<h3>What are the relations in a right triangle?</h3>
The relations in a right triangle are given as follows:
- The sine of an angle is given by the length of the opposite side to the angle divided by the length of the hypotenuse.
- The cosine of an angle is given by the length of the adjacent side to the angle divided by the length of the hypotenuse.
- The tangent of an angle is given by the length of the opposite side to the angle divided by the length of the adjacent side to the angle.
For this problem, we have that:
- The opposite side to the angle of depression is the top of tower, at a height of 9000 feet.
- The adjacent side to the angle is the distance to the bird, of 6000 feet.
Hence, considering θ as the depression angle, we have that:
tan(θ) = 9000/6000
tan(θ) = 1.5
θ = arctan(1.5)
θ = 56.31º.
More can be learned about relations in a right triangle at brainly.com/question/26396675
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