HELP HELP
Tommy rides in a motorboat against a river current for 25 km. Then he returns to his starting point by floating down river on a raft. Tommy travels 10 hours less on the motorboat than on the raft. Find the speed of the river current if the speed of the motorboat in still water is 12 km/h.

Answers

Answer 1

The speed of current is [tex]\rm 2 \:km/h[/tex].

What is the relation between distance,speed and time?

The relationship between distance, time and speed can be presented as:

[tex]\begin{aligned} \rm Distance &= Speed \times Time\\\\Speed &= \dfrac{\rm Distance}{Time} \\\\\rm Time &= \dfrac{\rm Distance}{\rm Speed} \end[/tex]

Calculations:

Given:

[tex]\begin{aligned} \rm Distance\: traveled\: on\: motorboat &= 25\:km\\\rm Speed\:of\:motorboat\:in\:still\:water &= 12\:km/h \end[/tex]  

 

Let the speed of the current be [tex]\rm x[/tex]

 

The speed of the boat traveling against the current is [tex]{(12 -\rm x) km/h}[/tex]

 

Time spent on motorboat is 10 hours less than time spent on raft.

Therefore:

[tex]\rm \dfrac{25km}{x\:km/h} - \dfrac{25km}{(12 - x)km/h} = 10[/tex]


The equation obtained will be:

[tex]\dfrac{25}{\rm x} - \dfrac{25}{(12-\rm x)} - = 10[/tex]

 

Multiplying both sides of the equation by [tex]\rm x(12 - x )[/tex]

[tex]\begin{aligned} \rm 25(12 - x) - 25x &= 10\times \rm x(12 - x)\\\\300 - 25x - 25x &= 120x - 10x^2\\\\300 - 50x &= 120x - 10x^2\\\\10x^2 - 120x - 50x + 300 &= 0\\\\10x^2 - 170x +300 &= 0\end[/tex]

Dividing the equation by 10

[tex]\rm x^2 - 17x + 30 = 0[/tex]

On factoring the equation,

[tex]\rm =x^2 - 2x -15x + 30 = 0\\\\=x(x - 2) -15(x - 2)\\\\=(x - 2)(x - 15)[/tex]

The values of x is 2 and 15.

Since speed of current i.e  [tex](12 -\rm x)km/h[/tex] cannot be negative, [tex]\rm x = 2[/tex] is the only acceptable value.

 Therefore the speed of current is 2 km/h.

Learn more about the topic here:

https://brainly.com/question/2292310


Related Questions

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Answer:

18/20 chance

Step-by-step explanation:

if you have 20 total marbles and two are green you have to subtract two because we are finding out the probability of NOT getting a green marble

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Answer:

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Step-by-step explanation:

He read for 2 hours and 15 minutes

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Step-by-step explanation:

Answer:

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Step-by-step explanation:

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Answers

Answer:

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Step-by-step explanation:

17/1 x 5/8. Multiply numerators together and denominators you will get 85/8. Then you convert the improper fraction.

Answer:

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Step-by-step explanation:

17 × 5/8  = 85/8

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Convert improper fraction to mixed number

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Answers

Answer:

[tex]P(32) = \frac{1}{90}[/tex]

[tex]P(Odd) = \frac{1}{2}[/tex]

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Step-by-step explanation:

Given

Sample Space = 10 to 99

First, we calculate the sample size (n)

[tex]n = 99 - 10 + 1[/tex]

[tex]n = 90[/tex]

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In 10 to 99, there is only 1 32.

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[tex]P(32) = \frac{n(32)}{n}[/tex]

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[tex]n(Odd) = 45[/tex]

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[tex]P(Odd) = \frac{n(Odd)}{n}[/tex]

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Solving (c): P(Multiple of 5)

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i.e

[tex]P(Multiples\ 5) = \frac{18}{90}[/tex]

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Answer:

0.625

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20+12=32 . ( amount of total pupils)

20/32=0.625  

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Answer:

very good im famous biol How to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerHow to add a great answerigist

Step-by-step explanation:

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Answer: 45 feet 1 yard= 3 feet so 3 feet times 15 is 45 feet

Step-by-step explanation:

Answer:

45 ft

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15 yd = 45 ft

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Answers

The answer is A I think sorry if I’m wrong
A is for apple ......................

The Gable Construction Corporation has placed bids for installing electronic message boards on two different highways.
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Answers

Answer:

0.64 = 64% probability that they will be awarded the contract for either the Macon Expressway or the Seaview Expressway

Step-by-step explanation:

We solve this question using these events as Venn sets.

I am going to say that:

Event A: Awarded the Macon Expressway.

Event B: Awarded the Seaview Expressway.

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This means that [tex]P(A) = 0.65[/tex]

The probability that they will be awarded the Seaview Expressway contract is 0.43.

This means that [tex]P(B) = 0.43[/tex]

Furthermore, the probability that they will be awarded both contracts is 0.22.

This means that [tex]P(A \cap B) = 0.22[/tex]

What is the

Probability that they will be awarded the contract for either the Macon Expressway or the Seaview Expressway?

Only A:

[tex]P(A) - P(A \cap B) = 0.65 - 0.22 = 0.43[/tex]

Only B:

[tex]P(B) - P(A \cap B) = 0.43 - 0.22 = 0.21[/tex]

Either

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If you buy 4 turkey subs that in total costs 26 dollars how much would 5 turkey subs cost.

Answers

Answer:

33/32.5

Step-by-step explanation:

26 divided by 4 equals 6.5

then 6.5 times 5 equals 32.5

The profit for a company this year was $100,000. Each year the profit increases at a rate of 1.2% per
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Answers

Given:

Initial profit = $100,000

Increasing rate of profit = 1.2%

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The function that shows the company's profit as a function of time in years.

Solution:

The exponential growth model is defined as:

[tex]f(t)=a(1+r)^t[/tex]

Where, a is the initial value, b is the growth rate and t is the time period.

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[tex]f(t)=100,000(1+0.012)^t[/tex]

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Answers

Answer:

y = mx+b is the equation for slope-intercept form

Step-by-step explanation:

m=slope

x=independent variable

y= y-intercept

Answer:

y=-2x

Step-by-step explanation:

100 - 50 + 4

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Answers

Answer:

54

Step-by-step explanation:

100-50+4=50+4

=54

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The answer is -4.29523809524 . (The second period is NOT another point. It’s just marking the end of a sentence. Yes, I’m a grammar & math freak)

Answer:

-4.29523809524

Step-by-step explanation:

A certain town never has two sunny days in a row. Each day is classified as being either sunny, cloudy (but dry), or rainy. If it is sunny one day, then it is equally likely to be either cloudy or rainy the next day. If it is rainy or cloudy one day, then there is 60% of chance that it will be the same the next day, and if it changes then it is equally likely to be either of the other two possibilities. In the long run, how frequent are we observing a day for which it is rainy and the next two days are also rainy

Answers

Answer:

In the long run if one day is rainy there is frequency of 2/5 that other two days will also be rainy.

Step-by-step explanation:

A matrix is formed to classify the weather conditions. It is given that if one day is sunny then there is likely chance that the next day will be cloudy, but if one day is rainy then there is 60% chance that next day will be same. To identify the possibility of next two days we create probability matrix;

Probability (P) = [tex]\left[\begin{array}{ccc}0&\frac{1}{2} &\frac{1}{2} \\\frac{1}{4} &\frac{1}{2} &\frac{1}{4} \\\frac{1}{4} &\frac{1}{4} &\frac{1}{2} \end{array}\right][/tex]

After solving for probability we get a fraction of 2/5

Answer 1 and 2 for brainliest

Answers

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Answer these correctly I’ll give brainalist + 10 points

Answers

first one is choice 1 second one is choice 3

Select all the expressions that could represent the volume of a box, which is a third degree polynomial in variables x and y.

A. 3 x y − 3 x y^2
B 2y-xy^3+7
C.3x^3y^2-3x^2y+10y^2-10y
D. 3x^2y+5xy
E. 3y^3+3x^3y^4

Answers

Answer:

A and D

Step-by-step explanation:

Third degree polynomials refers to polynomials that has 3 as the greatest power of the variable.

A. 3 x y − 3 x y^2

Degree = 1 + 2 = 3

This option is correct

B 2y - xy^3 + 7

Degree = 1 + 3 = 4

This option is wrong

C. 3x^3y^2 -3x^2y + 10y^2 - 10y

Degree = 3 + 2 = 5

This option is wrong

D. 3x^2y+5xy

Degree = 2 + 1 = 3

This option is correct

E. 3y^3 + 3x^3 y^4

Degree = 3 + 4 = 7

This option is wrong

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Answers

The answer is A I think

Pierre found a new store where he hopes to save
money on his supplies. He bought 4 brushes and 7
tubes of paint for $32. He has another order for 6
brushes and 8 tubes of paint that will cost $43.
What is the cost of one brush? What is the cost of
one tube of paint?

Answers

Your first equation is 4x + 7y= 32, the x’s representing the brushes and the y’s the tubes of paint. Our second equation is 6x+8y=43. What I did is I multiplied the first equation by 1.5 so that it turns into 6x+10.5y=48. Then I subtracted the second equation from the first, canceling out the x’s and leaving us with 2.5y=5. Then divided and got y=2. We then go back to any of the original equations and plug it in to get the x’s.
6x+8(2)=43. We get 6x+16=43. We subtract and are left with 6x=27 and then x=4.5. Then plug both of them in to a different equation to double check. You could also use substitution by isolating one of the variables in one equation and then plugging it in to the other one.

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Answers

Answer:

2/9 in the simplist form

Step-by-step explanation:

you multiply both the fractions for the area

then simplify

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