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:
The probability is 5/7
Step-by-step explanation:
In this question, what we are simply asked to calculate is that what is the probability of selecting a week day from the number of days in a week
The days in a week are ; Sunday Monday Tuesday Wednesday Thursday Friday Saturday
The total number of days in a week is thus 7
The weekdays are Monday Tuesday Wednesday Thursday Friday
The number of weekdays are 5
Thus, the probability of selecting a weekday by Edith is simply 5/7
Answer:
14/72
Step-by-step explanation:
Just line them all up and multiply numerators with numerators and denominators with denominators. You have your answer.
Answer:
The width will be 1.5 feet and the length will be 1.25 feet.
Step-by-step explanation:
12/8=1.5
10/8=1.25
10) 23710, 23715, 23751
11) 5206, 52701, 54025
12) 456231, 456321, 465321
13) 329854, 330820, 303962
14) dec, oct, nov
15) colorado, arizona, new mexico
