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.
I believe if I did the expression correctly, the solution is 1
Answer:
Aplles are 25%.
Step-by-step explanation:
Answer:
Point of x-intercept: (2,0).
Point of y-intercept: (0,6).
Step-by-step explanation:
1. Finding the x-intercept.
This point is where the graph of the function touches the x axis. It can be found by substituting the "y" for 0. This is how you do it:
Hence, the point of x-intercept: (2,0).
2. Finding the y-intercept.
This point is where the graph of the function touches the y axis. It can be found by substituting the "x" for 0. This is how you do it:
Hence, the point of y-intercept: (0,6).
