Johnny and his father go fishing at 5:00 AM. After motoring 6 km upstream, Johnny writes a letter to his friend, puts the letter in a bottle, and drops it into the river. The bottle floats in the current and reaches at 7:40 AM the point where Johnny and his father began their trip. If the speed of the boat in still water is 9 km/h, what is the speed of the river current?

Answers

Answer 1

Answer:9/2 km per hour

Step-by-step explanation:

equation,

6/9-x + 6/x=8/3

Answer 2

Upstream is flowing of the boat in the opposite direction of the stream. The speed of the river current is 4.5 km per hour.

Given-

Johnny and his father go fishing at 5:00 AM.

Total traveled by the Johnny and his father in upstream is 6 km.

The speed of the boat is 9 km/h.

What is upstream?

Upstream is flowing of the boat in the opposite direction of the stream.

Let x be the speed of the river current.

Time taken by the Johnny and his father to travel 6 km in upstream is ,

[tex]=\dfrac{6}{9-x}[/tex]

The time taken by the bottle to floats in the current river is,

[tex]=\dfrac{6}{x}[/tex]

As Johnny and his father start from 5:00 AM and the bottle reached to the point where Johnny and his father began their trip at 7:40 AM. Thus the total time is,

[tex]=7:40-5:00[/tex]

[tex]=2:40[/tex]

In hours,

[tex]=2\dfrac{40}{60}[/tex]

[tex]=\dfrac{8}{3}[/tex]

As the total time is equal to the sum of the Time taken by the Johnny and his father to travel 6 km in upstream and The time taken by the bottle to floats in the current river. Thus,

[tex]\dfrac{6}{9-x}+\dfrac{6}{x}=\dfrac{8}{3}[/tex]

[tex]\dfrac{6x+54-6x}{9x-x^2}= \dfrac{8}{3}[/tex]

[tex]\dfrac{27}{9x-x^2}= \dfrac{4}{3}[/tex]

[tex]x^2-9x+\dfrac{81}{4}=0[/tex]

On solving the above quadratic equation we get the positive value of the x is 4.5.

Thus the speed of the river current is 4.5 km per hour.

Learn more about the upstream here;

https://brainly.com/question/7567233


Related Questions

Reflect line AB over the y axis HELP PLS

Answers

Answer:

Here is the answer

And I have a problem

Step-by-step explanation:

Solve for x.

16 = -2x - 1

Solve for x.

16 = -2x - 1

pls

Answers

Answer:

1. 7

Step-by-step explanation:

Answer:

x = 7 [tex]\frac{1}{2}[/tex]

Step-by-step explanation:

From the set {5, 9, 12}, use substitution to determine which value of x makes the equation true. 12(x - 4) = 96

Answers

Answer:

12

Step-by-step explanation:

12(5-4)=96

60-48=12 means it's not five

12(9-4)=96

108-48=60 means it's not 9

12(12-4)=60

144-48=96 so answer is 12

Can a triangle have side lengths 4, 4, 7?
1.no
2. Yes
3. not enough information

Answers

Yes! The lengths of each side must be less than the sum of the other two lengths. It looks like this:
4+4>7
7+4>4
4+7>4

Write and solve a proportion to answer the question. 36 is 0.9% of what number w? 36/w = .9/100 what is w? w = ?

Answers

Answer:

4000

Step-by-step explanation:

To solve :

36 = 0.9% of w ; solve for w

36 = 0.9/100 * w

36 = 0.009w

Divide both sides by 0.009

36/0.009 = 0.009w / 0.009

4000 = w

Hence, the number, w equals 4000

Start at the origin. Move 3 units right and 1 unit up. What is the ordered pair at this point ? for brainlest!!!

Answers

Answer:

(3,1) should be the answer

Step-by-step explanation:

Hope this helps!

The ordered pair at this point is (3,1)

How to draw a shifted figure if the shifts are provided?

Suppose the graph is drawn on the coordinate plane.

Let the shifting be (x,y) → (x+a, y+b)

Then, add 'a' to all x coordinates of the graph's points. Add 'b' to all y coordinates of the graph's points.

The resultant set of new points will be plotted.

Given;

From origin; move to right 3units

                     move upward 1unit

Moving to right 3units;

(0,0)= (3,0)

Move upward 1unit;

(3,0)= (3,1)

Therefore, the point on graph after shifts will be (3,1)

Learn more about graphs here:

https://brainly.com/question/26254258

#SPJ2

Indicate in standard form the equation of the line passing through the given point and having the given slope.

R = (4, 0), m = 5

Can someone help with this?

Answers

0=5(4)+b is how the equation needs to be worked out

Hiiiooos! Can someone please help me with this!!!❤️❤️❤️❤️:)

Answers

Answer:

a

Step-by-step explanation:

hopes this helps

Answer: My best guess is 10 (sqrt of 2)

Step-by-step explanation:

Which describes the location of 0.65 on the number line?
A) between 1/2 and 2/3 b) between 2/3 and 7/10 C) between 7/10 and 4/5 D) to the right of 4/5

Answers

Between the 1/2 and 2/3 :)

please help i don’t understand this

Answers

Answer:

slope of line one: 2/4 or 1/2

line two: 6/1

line 3: 6/3 or 2

line 4: -4/1

to find the slope of a line, you have to use rise/run the number of space going along the y-axis is the rise, and the space of the points on the x-axis is the run.

hope this helps!

how do u make 24 out of the numbers(7)(7)(7)(5)
using only [×][-][÷][+]
frist to get this right gets brainlyest

Answers

Answer: You add all the numbers.

Step-by-step explanation:

7 + 7 + 5 + 5 = 24.

:)

(7-7/7)*4=24


i know this because i solved it

Pythagorean Theory

I need help...

Answers

Answer: 12

Step-by-step explanation:

Write the equation of the line in fully simplified slope-intercept form.

Answers

Answer:

[tex]y = -\frac{2}{5} x-6[/tex]

Step-by-step explanation:

1) First, find the slope of the line. Use the slope formula [tex]m =\frac{y_2-y_1}{x_2-x_1}[/tex]. Pick two points on the line and substitute their x and y values into the formula, then solve. I used the points (-5,-4) and (0,-6):

[tex]m = \frac{(-6)-(-4)}{(0)-(-5)} \\m = \frac{-6+4}{0+5} \\m = \frac{-2}{5} \\[/tex]  

So, the slope of the line is [tex]-\frac{2}{5}[/tex].

2) Next, use the point-slope formula [tex]y-y_1 = m (x-x_1)[/tex] to write the equation of the line in point-slope form. (From there, we can convert it to slope-intercept form.) Substitute values for the [tex]m[/tex], [tex]x_1[/tex] and [tex]y_1[/tex] into the formula.

Since [tex]m[/tex] represents the slope, substitute [tex]-\frac{2}{5}[/tex]  in its place. Since [tex]x_1[/tex] and [tex]y_1[/tex] represent the x and y values of one point on the line, pick any point on the line (any one is fine, it will equal the same thing at the end) and substitute its x and y values in those places. (I chose (0,-6), as seen below.) Then, with the resulting equation, isolate y to put the equation in slope-intercept form:

[tex]y-(-6) = -\frac{2}{5} (x-(0))\\y + 6 = -\frac{2}{5} x\\y = -\frac{2}{5} x-6[/tex]

HELP ME PLESE IM TIMED NO SNEAKY LINKS ANWSERS ONLY PLZZZ HELP ME

Answers

Answer:

8p=t

Step-by-step explanation: Snap add?

Answer:

8p = t

Step-by-step explanation:

Length of one string = p

Length of all the strings (t) = p × 8

                                            = 8p

Thus, 8p = 7

please help ASAP !!
Choose the system of equations that matches the following graph:
Picture included!

Answers

Answer:

Choice 2

Step-by-step explanation:

If im wrong im so sorry

If im right can i hav brainliest plz?

Answer:

b

Step-by-step explanation:

So you start at x-axis work your way down to the y-axis and you get your answer.

Mr Jones bought a snowboard. The 6% sales tax on the snowboard was $32.50. What was the total cost including the sales tax? (rounded to nearest cent)

Answers

Answer: $574

Step-by-step explanation:

First we need to calculate the price of the snowboard before the addition of the tax. This will be represented by x. Therefore,

6% of x = $32.50

0.06 × x = $32.50

0.06x = $32.50

x = $32.50 / 0.06

x = $541.67

Therefore, the total cost including the sales tax will be:

= $541.67 + $32.50

= $574.17

= $574

Karl is comparing the interest rates for accounts at two different banks. He will deposit $600 into an account and will not make any additional deposits or withdrawals. Bank Q offers 1% interest compounded annually. Bank R offers 1.5% simple interest.

Answers

Answer: bank R for 1 year

Step-by-step explanation:

Given

Principal deposit is [tex]P=\$600[/tex]

Bank Q offers 1% interest compounded annually

Bank R offers 1.5% simple interest annually

For Bank Q, Compound interest is given by

[tex]\Rightarrow P[1\frac{R}{100}]^t-P[/tex]

for 1 year it is

[tex]\Rightarrow 600[1+\frac{1}{100}]-600=\$6[/tex]

For bank R, simple interest is

[tex]S.I.=\dfrac{P\times R\times T}{100}[/tex]

for 1 year it is

[tex]\Rightarrow S.I.=\dfrac{600\times 1.5\times 1}{100}=\$9[/tex]

Clearly, bank R offers more interest for 1 year

we can ise the distance formula or pythagorean theorem to find the length of a segment? true or false

Answers

Answer:

I think its true

Step-by-step explanation:

question is in picture. Plzzz help me. Due in 2hrs

Answers

Answer:

I think it's line "A"

Step-by-step explanation:

What is the box-and-whiskers plot used to show?
a. a histogram
c. median
b. variability
d. observations

Answers

Answer:

b and c

Step-by-step explanation:

box-and-whiskers plot shows the shape of the distribution, its central value, and its variability.

A triangle's side lengths are 15 cm and 10 cm. Write an inequality to determinte the possible measure for the missing side length.

Answers

Answer:

the missing side lenght = x

0 < x < 15+10

0 < x < 25 cm

Solve 7x − 2(x + 1) = 6x + 14. (5 points)

−12

12

−16

16

Answers

Answer:

C

X=-16

Step-by-step explanation:

Its all in the picture-

Answers

62%
................................

Of the 16 people attending a seminar, 2 have blond hair.
What is the probability that a randomly selected person will have blond hair?

Answers

Answer:

1/8

Step-by-step explanation:

A stick is 6 m long. A rope is 2 times as long as the stick.
(NO SCAMS OR UNKNOWN LINKS! If u do try to, I will immediately report you, without hesitation..)

Answers

Answer:

Step-by-step explanation:

wouldn't it be 12  meters? is this isn't what you need ill figure it out and edit this

What to say back if someone told you that your cute

Answers

Answer:

your cute to

Step-by-step explanation:

Answer:

lol id.k

Step-by-step explanation:

if they cute too say " ty u too;)"

jp I'm bad at giving advice...


Please help me with this !

Answers

Answer:

a. 4 (or maybe like 3.5)

b. 6

Step-by-step explanation:

a. Going from x = 0 to x = 8, it is obvious that y goes down 4 or 4.5 units during this stretch. This gives an approximate slope of -3/8. With this in mind, it can be easily calculated that going the remaining distance from x = 8 to x = 10, the value of y will be approximately 4 or so.

b. A dot literally is right next to (6, 6).

Makayla is flying a kite. The angle of elevation from Makayla to the kite is 58º. If 55 ft of kite string has been used, how high above the ground is the kite, to the nearest foot? ​

Answers

Answer:

I dont know good luck :)

Step-by-step explanation:

peace

if you are smart I will give brainliest

2 + 2enty = ???

Answers

Answer:

2enty 2

Step-by-step explanation:

I think it’s 40, have a great day!!!

PLEASEEEE HURRY

For the linear function represented in the table below, determine the value of y if x = 6.

Answers

Answer:

22

Step-by-step explanation:

The y values increase by 2 every time so 18+2=22

Other Questions
What is the area of this. ASAP What do they feel about dead ancestors in Ancient China? (How were they connected) a dialogue between summer and spring about who is a better season Please help ASAPIll mark BrainliestWhats the total and lateral surface area for the figure? Which is a solution of the equation?2x - y = 5O 7O (3,-1)O (2,-1)O (1,2) In which states do Presidential candidates concentrate their election campaigns? Can someone pleaseeee help and if youre correct ill give brainliest (61)+(1 100 1 )left parenthesis, 6, times, 1, right parenthesis, plus, left parenthesis, 1, times, start fraction, 1, divided by, 100, end fraction, right parenthesis = 6.16.1 7th Grade Mock EOG - Math NeTriangle JKL is an isosceles triangle. Side JL measures 8 inches and side KL measures 17 inches. What is the measure of the side JK?A. 8 inchesOB. 9 inches0 C 12 inchesOD. 17 inchesFrelor Can you help me with biology? what is the next number in sequence -2, 10 -50, 250 Please help me please Where is 5/4 on a number line Multi-Level-Marketing is a quickly growing industry in the United States. Many men and women are deciding to work from home, selling various goods to their friends and family due to the convenience and possible salary that can be made. Multi-Level-Marketing consists of a hierarchy of workers and customers and is sometimes referred to as a pyramid scheme I need number 1 and 2 and 3 and 4 pleaseeeeer The average person's stride lenghth the distance covered by one step is aproximently 2.5 feet long. How many steps would the average person take to travel 50 feet? Can someone please verify if these are the right answers? Thank you! Who has the answers for the passport.carnegielearning.com What do you burn a CD with?un bruneur de CD-Romun gravier de CD-Romun graveur de CD-Romun burnier de CD-Rom How did the scope of American literature change in the first half of the 20th century?