A fish swims upstream a distance of 16 miles in a river with a current of 3 miles per hour. The fish returns swimming
downstream the same distance. The roundtrip up and down the river takes the fish 4 hours. Assuming that the fish
swims at a constant speed in still water, what is the fish's speed in still water?

Answers

Answer 1

Answer:

9 mph = the speed in still water

Step-by-step explanation:

Let r = the speed in still water

Then the speed going down stream is r + 3

and the speed going upstream is r - 3

d = rt   or t = d/r

time going downstream is 16/(r + 3) and time going upstream is 16/(r - 3)

The total time was 4 hours, so

[tex]\frac{16}{r + 3} + \frac{16}{r - 3} = 4[/tex]   Multiply thru the equation by (r + 3)(r - 3)

Then 16(r - 3) + 16(r + 3) = 4(r + 3)(r - 3)

         16r - 48 + 16r + 48 = [tex]4r^{2}[/tex] - 36

         [tex]4r^{2}[/tex] - 36 = 32r

         [tex]4r^{2}[/tex] - 32r - 36 = 0

         [tex]4(r^{2} - 8r - 9) = 0[/tex]

         4(r - 9)(r + 1) = 0

             r = 9  or -1

But a rate of speed cannot be negative, so x ≠ -1

So, r = 9 mph = the speed in still water


Related Questions

Which set of side lengths will form a right triangle?

7, 24, 25
5, 11, 13
8, 13, 17
9, 24, 25

Answers

Answer:

7, 24, 25

Step-by-step explanation:

Answer:  [tex]7, 24, 25[/tex]

Step-by-step explanation:

Hi there!

We can solve this using the Pythagorean Theorem. The Pythagorean Theorem states that in a right triangle, a^2 + b^2 = c^2. We can plug each set of numbers into the equation, one by one, to see if the set of numbers is true in the equation. One thing to note is that the largest number out of the set is always the hypotenuse, or c. The other numbers are the legs (a and b.)

5, 11, 13

a^2 + b^2 = c^2

(5)^2 + (11)^2 = (13)^2

25 + 121 = 169

146 ≠ 169

Since 146 doesn't equal 169, this is NOT a right triangle

9, 24, 25 a^2 + b^2 = c^2 (9)^2 + (24)^2 = (25)^2 81 + 576 = 625 657 ≠ 625

Since 657 doesn't equal 625, this is NOT a right triangle

7, 24, 25 a^2 + b^2 = c^2 (7)^2 + (24)^2 = (25)^2 49 + 576 = 625 625 = 625

This equation is true, because 625 = 625. Therefore this IS a right triangle.

HELP PLEASE ASAP!!!!!!!!!!!!!

Answers

Answer:

b

Step-by-step explanation:

What’s the answer??????

Answers

Answer:

x=50

Step-by-step explanation:

Answer:

x = 50

Step-by-step explanation:

So the equation is 2x+25=125. you first subtract the 25 from the 125 which you'll get 100 and then divided by 2 which leaves the x alone and so 100/2 = 50 so x= 50

Find the surface area of the rectangular prism

Answers

The team go skirt pop pop pop pop pop pop...

April and Bill went to the grocery store to buy chocolate bars. April bought 4 small chocolate bars and 6 large chocolate bars , while Bill bought 4 small chocolate bars and 3 large chocolate bars. If April paid $16.50 and Bill paid $11.25, what is the price of a single large chocolate bar?

Answers

Step-by-step explanation:

To  do this equation, we could put it in terms of algebra, lets say the large chocolate bars are represented by L and the small bars by S

April

4S + 6L = $16.50

Bill

4S + 3L = $11.25

Looking at this, we can see that the difference between the two purchases is that Bill bought three less large chocolate bars, this means the difference in total cost equals three large chocolate bars. Using this knowledge.

$16.50 minus $11.25 = $5.25

$5.25 = Three Large Bars

Divide this by three to get the cost of one large bar.

$1.75 is the cost of one single large bar.

Answer:

April: 4x+6y=16.5

Bill: 4x+3y=11.25

solving the two equations simultaneously will give you y=1.75

√20/125 answer in simpleset form

Answers

Answer:

.4!

Step-by-step explanation:

first you divide 20 by 125 and get .16

then you take the square root of .16 and get .4

y = 4x - 6
y = 4x + 10
What is the solution to the system?

Answers

Answer:

No Solution

Step-by-step explanation:

y = 4x - 6

y = 4x + 10

You can set them equal to each other because they both are y.

4x-6=4x+10

-6=10

No Solution

How do you find the radius of a circle ​

Answers

Answer

Just remember to divide the diameter by two to get the radius.

Step-by-step explanation:

If you were asked to find the radius instead of the diameter, you would simply divide 7 feet by 2 because the radius is one-half the measure of the diameter. The radius of the circle is 3.5 feet. You can also use the circumference and radius equation

In ΔMNO, the measure of ∠O=90°, the measure of ∠N=26°, and NO = 5.1 feet. Find the length of OM to the nearest tenth of a foot .

Answers

Answer:

x=2.4874≈2.5 feet

Step-by-step explanation:

tanN=

adjacent

opposite

=

5.1

x

\tan 26=\frac{x}{5.1}

tan26=

5.1

x

5.1\tan 26=x

5.1tan26=x

y=4x-16. Please Show work

Answers

Answer: x=4

Step-by-step explanation:

Step 1. turn you y into a 0

0=4x-16

Step 2. get x alone

a.

0  =  4x  -16            

+16           +16

*what you do to one side of the equal sign you must to the other.

b.

0 + 16 = 4x

(divide by 4)  16 = 4x  (divide by 4)

*divide by 4 to get rid of the 4 next to the x, remeber to do both sides of the equal sign

4 = x

Which of the following could be the graph of the line y = 3x - 2?

Answers

You didn't give a graph but I will visualize what it looks like for you.

The line is going through (0,-2) because that is the y-intercept.

The line has a slope of 3.

So, the line goes through:

(1,1)

(2,4)

(3,7)

(4,10)

(5,13)

Since there is no picture provided, I can't give you the answer, but I can help you solve it.  

To solve this you have to first look at the b part of the formula y=mx+b, so -2.

Then, you can find -2 on the y-axis (the vertical axis)

and then you could move upwards 3 spaces, then right 1 space.

You would do this as the slope is 3/1 (the mx part of the equation).

Finally, you continue to move up 3, and right 1 until there are enough points on the graph to make a line, and that will help you see what graph is correct.

It should look something like this:

a ship sails 20km due north. It changes direction and then sails 15 due east. How far is it from its starting point? ​

Answers

It is 35km from its starting point

If Maureen from example 3 works overtime, she receives an hourly rate times her regular hourly rate. What is Maureen's hourly overtime rate?

Answers

9.70(1.5) = 14.55 ; Maureen's hourly overtime rate is $14.55

16)
An object is launched from ground level with an initial velocity of 120 meters per second. For how long is the object
at or above 500 meters (rounded to the nearest second)?
The equation that models the path of the object is y=-4.912 + 1200.
A)
11 seconds
B)
12 seconds
13 seconds
D)
14 seconds

Answers

It’s 11 seconds u need to round so you add then round there is your answer

Which regular polygon would have each of its interior angles measure 120°?

nonagon
hexagon
octagon
heptagon

Answers

The correct answer is Hexagon

Answer:

Hexagon

Step-by-step explanation:

If in a regular polygon, each interior angle = 120 deg, then each exterior angle = 180–120 = 60 deg. So the polygon has 360 deg/60 deg = 6 sides. The figure is a regular hexagon.

PLEASE ANSWEAR IM FALLING MATH :((( .. Maniah has a meal in a restaurant. She adds up the prices listed on the menu for everything they ordered and gets a subtotal of $57. When the check comes, it says they also need to pay $4.23 in sales tax. What percentage of the subtotal is the sales tax?

A.
2.41%

B.
0.0742%

C.
4.23%

D.
7.42%

Answers

Answer:

D

Step-by-step explanation:

To find the answer, input this into your calculator

4.23/57 × 100

This gives the percentage of 7.42% (rounded)

hope this helps :)

The smallest known female spider is 23/50 millimeter long. The smallest male spider is 37/100 millimeters long. Write each fraction as a decimal.

Answers

Answer:

23/50 = 0.6 and 37/100 = 0.37

Step-by-step explanation:

A recipe requires 4 cups of milk you can only use 3/4 how many 3/4 cups do you need

Answers

Answer:

You would need 5 3/4 cups of milk.

Step-by-step explanation:

It's right! Brainliest?

9. What is the sales tax on an item that costs $67.00 if the state sales tax is 6.5%?

A. $435

B. $4.35

C. $3.35

D. $.45

Answers

Answer:

B

Step-by-step explanation:

Answer:

B. $4.35

Step-by-step explanation:

to find your sales tax you just have to do [cost of the item] x [ percentage as a decimal]= sales tax

so in your case it would be [$67.00] x [0.065] = $4.35

y=(8/7)x
growth or decay?

Answers

Growth

Step-by-step explanation:

Answer:

Growth

Step-by-step explanation:

Increasing rate greater than 1. It would be decay if it was less than 1.

The angles of a triangle are 44°,110°, and 26° Classify the triangle

Answers

Answer:

The triangle is a scalene triangle because it has no line symmetry

Step-by-step explanation:

What is the variance of the data set (4,6,7,10)​

Answers

Answer:

4.6875

Step-by-step explanation:

Given data set

(4,6,7,10)​

To find

Variance

Solution

The Variance is defined as the average of the squared differences from the mean.

The mean is:

x = (4 + 6 + 7 + 10)/4 = 6.75

The variance is:

σ² = [(4 - 6,75)² + (6 - 6.75)² + (7 - 6.75)² + (10 - 6.75)²]/4 = 4.6875

You roll a number cube 600 times, Theoretically, how many times should you roll an odd
number?

Answers

Answer:

300?

Step-by-step explanation:

Translate the verbal expression to an algebraic expression: Twice the sum of a number and 4. Gimme an answer quick. In a SENTENCE

Answers

Answer:

2(x+4)

Step-by-step explanation:

Brainliest are appreciated :)

Answer:

if x=3 what is the value of this expression

Step-by-step explanation:

6,750,000 is what % of 9,000,000

Answers

Answer:

P = 9000000 × 6 100 = 9000000 × 0.06 = 540000 (answer) Therefore, the answer is 540000 is 6 percent of 9000000. Solution for '6 is what percent of 9000000?' The following question is of the type "P is what percent of W,” where W is the whole amount and P is the portion amount".

Answer:

75%

Step-by-step explanation:

I subtracted 6,750,000 from 9,000,000 and got 2,250,000.

I realized that that 2,250,000 is 25% of 9,000,000 so that leaves the remaining 6,750,000 to be 75%.

i am sorry if this doesn't make sense but that is how i figured it out.

Enter an inequality that represents the phrase the sum of 1 and y is greater than or equal to 7.

Answers

Answer:

y ≥ 6

Step-by-step explanation:

y + 1 ≥ 7

y ≥ 6

Round 94584 to the nearest hundreds

Answers

Answer:

94600

Step-by-step explanation:

A hundred has 2 zeroes. To round a number to the nearest hundreds, just look at the last 2 digits (84). If it is 5 or bigger, add 1 digit (as I did in this exercise) and so it becomes 94600.

Evan is going to the county fair this weekend. The admission to the fair is %5 and the cost per ride is 50 cents. What is the rate of change (slope) of this problem?

Answers

Answer:

$0.50/ride

Step-by-step explanation:

That rate of change (unit rate) is $0.50/ride.  

This is also the slope of the graph.  $5 is the y-intercept.

im new can anyone help

Answers

Answer:

We have the equation:

[tex]W = W_0*(\frac{1}{2})^{0.36*t}[/tex]

Where:

W₀ is the initial area of the wound, and t is the time in days.

Now, if we initially have a wound of 25 mm^2, then:

W₀ = 25mm^2

And we can replace it in the equation, then we get:

[tex]W = (25mm^2)*(\frac{1}{2})^{0.36*t}[/tex]

We want to know the size of this wound after:

a) 1 day.

We know that t represents time in days, so here we just need to replace t by one, then:

[tex]W = (25mm^2)*(\frac{1}{2})^{0.36*1} = 19.5 mm^2[/tex]

b) 1 week

Again, t represents the time in days, so we need to write this in days.

We know that:

1 week = 7 days.

then t = 7

The size of the wound after 7 days is:

[tex]W = (25mm^2)*(\frac{1}{2})^{0.36*7} = 4.36 mm^2[/tex]

what is the height from the base of the statue to the tortch in inches

Answers

Answer: OK so I think Her Size (In a case like this it's ok to ask her size without getting in any trouble.): Her total overall height from the base of the pedestal foundation to the tip of the torch is 305 feet, 6 inches. Height of the Statue from her heel to the top of her head is 111 feet, 6 inches.

Step-by-step explanation:

This should be a simple problem, I think, simple calculate changing the feet to inches or yards, as the problem demands. I believe the height would be 1,813 inches (12 inches per foot), and the thickness of the arm would be 4 yards (3 feet per yard).

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