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:
<h2>Y = 22.56 cm </h2>
Step-by-step explanation:
To find the diameter Y of the circle we must first find the radius of the circle
Area of a circle = πr²
where
r is the radius
From the question
Area = 400cm²
Substitute the value into the above formula and solve for the radius
That's
400 = πr²
Divide both sides by π
We have
Find the square root of both sides
radius = 11.28 cm
Since we have the radius we can use it to find the diameter Y using the formula
diameter = radius × 2
radius = 11.28
Y = 11. 28 × 2
We have the final answer as
<h3>Y = 22.56 cm</h3>
Hope this helps you
Answer:
B) A line with a positive slope increases as it is viewed from left to right.
Step-by-step explanation:
A line with a positive slope increases as it is viewed from left to right.
A positive slope means that as a line on the line graph moves from left to right, the line rises.
Hope this helps :)
Answer:
Probability that event will have both red marbles will be 2.3% or 0.023.
Step-by-step explanation:
Given:
Total red marbles=5
Total blue marbles=25
Total number of marbles =30
To Find:
The probability that both are red without replacement of marbles.
Solution:
Now
Total sample space is 30 and total red marbles are 5
For a event that getting red marble probability is ,
=Total red marbles /total marbles.
=5/30
=1/6
So probability if getting red marble is 1/6
<em>Now for second chance there will be 4 red marbles remaining and 29 total marbles so,</em>
In second chance probability if getting red marble will be
=total red marbles present/total marbles remaining
=4/29
Now ,
The required probability will be getting both at a time
i.e probability getting red AND red marble so here AND operator which means multiple both the probability.
Probability both will have red =1/6*4/29
=4/(29*6)=2/(29*3)
=0.022988
=0.023
=2.3 %
Answer:
$1105.5
Step-by-step explanation:
825 X 0.34 =280.5
The 0.34 is the 34%
280.5 is what was discounted.
Then add 280.5 to 825 and that adds up to 1105.5
