Answer: obtuse
Step-by-step explanation:
Answer: 22 hours 11 minutes
<u>Step-by-step explanation:</u>
![22\ hours + \bigg[\dfrac{19}{100}=\dfrac{x}{60}\bigg]\\\\22\ hours + 11\ minutes](https://tex.z-dn.net/?f=22%5C%20hours%20%2B%20%5Cbigg%5B%5Cdfrac%7B19%7D%7B100%7D%3D%5Cdfrac%7Bx%7D%7B60%7D%5Cbigg%5D%5C%5C%5C%5C22%5C%20hours%20%2B%2011%5C%20minutes)
9514 1404 393
Answer:
D
Step-by-step explanation:
Solve x = f(y) for y.
x = ∛(y/9) -4
x +4 = ∛(y/9) . . . . . add 4
(x +4)³ = y/9 .. . . . . cube
9(x +4)³ = y . . . . . . multiply by 9
The inverse function is ...
f⁻¹(x) = 9(x +4)³ . . . . . matches the last choice
Let the speed of river be x km/hr down stream.
Time = Distance / speed
Since river flows downstream, speed of boat down stream = Speed of boat + speed of river = (15 + x).
Since river flows downstream, speed of boat upstream = Speed of boat - speed of river = (15 - x).
Time Upstream - Time Downstream = 75 minutes
Time Upstream = 45 / (15 - x)
Time Downstream = 45 / (15 + x)
75 minutes = 75/60 = 5/4 hours
Time Upstream - Time Downstream = 75 minutes = 5/4 hours
45 / (15 - x) - 45 / (15 + x) = 5/4 Divide both sides by 45
1 / (15 - x) - 1 / (15 + x) = (5/4)*(1/45)
1 / (15 - x) - 1 / (15 + x) = 1/36
((15 + x) - (15 -x)) / (15-x)(15+x) = 1/36
(15 +x - 15 +x) / (15-x)(15+x) = 1/36
2x / (15-x)(15+x) = 1/36
(15-x)(15+x) = 2x*36
(15-x)(15+x) = 72x
225 - x² = 72x
0 = x² + 72x -225
x² + 72x -225 = 0 This is a
quadratic function, use a calculator that can solve the function, by
inputting the function.
x = 3, or -75. Since we are solving for speed, we can not have negative values.
x = 3 is the only valid solution.
Speed of the river = 3 km/hr downstream.
Copyright.
Answer:
B. 20%
Step-by-step explanation:
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