1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
maksim [4K]
3 years ago
13

Tinh can row at a rate of 6 mph in still water. It takes her 2 hours to row upstream from a dock to a park. She then rows back t

o the dock, and it only takes 40 minutes. What is the speed of the river current? 3 mph 12 mph 18 mph 48 mph
Mathematics
2 answers:
scZoUnD [109]3 years ago
7 0

Answer:

Option A is correct, i.e. 3 mph.

Step-by-step explanation:

Tinh can row at a rate of 6 mph in still water.

Suppose the speed of the river current is X mph.

Then Upstream speed = (6-X) mph.

And Downstream speed = (6+X) mph.

It takes her 2 hours to row upstream from a dock to a park. She then rows back to the dock, and it only takes 40 minutes.

It means Distance upstream = Distance downstream.

Speed upstream x Time upstream = Speed downstream x Time downstream.

(6-x) * 2 = (6+x) * 40/60

12 - 2x = 4 + 2x/3

12 - 4 = 2x/3 + 2x

8 = 2x/3 + 6x/3 = 8x/3

x = 3 mph.

Hence, option A is correct, i.e. 3 mph.

Mariulka [41]3 years ago
7 0

Answer:

Option A (3)

Step-by-step explanation:

Given that Tinh can row at a rate of 6 mph in still water.

Also it takes her 2 hours to row upstream from a dock to a park. She then rows back to the dock, and it only takes 40 minutes.

While upstream she travels against the stream but while downstream she travels along with the stream

Let x  be the speed of boat in still water and y that of stream

Then since distance d is the same, time x speed =D

i.e. (x-y)120 = (x+y)40 after converting hours to minutes

80x=160y

x=2y

x=6 (given)

So y = 6/2=3 mph




You might be interested in
Which three-dimensional figure will this net make?
V125BC [204]
The shape for this net is the last one
3 0
3 years ago
Round 649,418 to the nearest ten,_____,nearest hundred_____,nearest thousand_____,nearest ten thousand_____,nearest hundred thou
kvasek [131]
649,420
649,420
649,420
650,000
700,000
4 0
3 years ago
Read 2 more answers
Consider the triangle.
allochka39001 [22]

Answer:

angle B, angle A, angle C

Step-by-step explanation:

4 0
3 years ago
A professor thinks that the students in her statistics class this term are less creative than most students at this university.
choli [55]

Answer:

It is not enough evidence to reject null hypothesis. It is not enough evidence to say that mean score is not equal to 35.

Step-by-step explanation:

\mu=35\\n=23\\\=x=33\\s=5\\\alpha=0.1

1. Null and alternative hypothesis

H_{0}:\mu=35\\H_{1}:\mu

2. Significance level

\alpha=0.1\\1-\alpha=0.99

Freedom degrees is given by:

v=n-1\\v=23-1=22

For a sgnificance level of 0,01 and 22 freedom degrees,  t-student distribution value is:

t_{0.01;23}=-2. 5083

3. Test statistic

t=\frac{\=x-\mu}{\frac{s}{\sqrt{n} } }

t=\frac{33-35}{\frac{5}{\sqrt{23} } }

t=-1,918

In this case, we have an one left tailed analysis, it means that null hypothesis is rejected if t

-1.918>-2.5083

Conclusion:

It is not enough evidence to reject null hypothesis. It is not enough evidence to say that mean score is not equal to 35.

3 0
3 years ago
A mathematical formula designed to predict population fluctuations in a community could be called a(an)
kvasek [131]
It would be called an ecological model.
5 0
3 years ago
Other questions:
  • In a right triangle, the length of the hypotenuse is 20 inches and the length of one leg is 15 inches. What is the length of the
    6·1 answer
  • Which of the following is a graph of y=3/2x2
    9·1 answer
  • 4) The diameter of a circle is 32m. The radius is represented by 4(x + 2).
    10·1 answer
  • For the following equation, what would you do first? -8n+4(1-5n)=-6n-14
    9·1 answer
  • PLEASE HELP ME I DONT UNDERSTAND THANK YOU!
    10·1 answer
  • –<br> 1<br> 3<br> 4<br> +<br> 3<br> 4<br> ×<br> –<br> 4÷2
    11·2 answers
  • Please help picture is there
    12·1 answer
  • 6÷2 (1+3)= what is the answer to this problem and why I say 1. some say 9.
    8·2 answers
  • the diagram shows a right-angled triangle ABC and a circle. A, B and C are points on the circle AB is a diameter of the circle A
    9·1 answer
  • If the graph passes the horizontal-line test, then the function is one-to-one. Functions that are one-to-one have inverses that
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!