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
cluponka [151]
3 years ago
11

A fisherman traveled in a boat from point N upstream. After having traveled 6 km, he stopped rowing and 2 hour 40 min after firs

t leaving N, he was brought back to N by the current. Knowing that the speed of the boat in still water is 9 km/hour, find the speed of the river’s current.
Mathematics
1 answer:
Nat2105 [25]3 years ago
6 0

Answer:

The speed of the river's current is 4.5 km/hr.

Step-by-step explanation:

Given : A fisherman traveled in a boat from point N upstream.

After having traveled 6 km, he stopped rowing and 2 hour 40 min after first leaving N, he was brought back to N by the current.

Knowing that the speed of the boat in still water is 9 km/hour

To find : The speed of the river’s current.

Solution :

Let the speed of current  = x km/h

Speed of boat = 9 km/h

Thus, the speed in upstream = (9 - x) km/h

Also, the speed in downstream = x km/h (because the boat is stationary in downstream)

Total distance = 6 km ( from N to the point he reached )

Total time = 2 hours 40 minutes

\text{2 hours 40 minutes}=2\frac{40}{60}=2 \frac{2}{3} \\\\\text{2 hours 40 minutes}=\frac{8}{3} \text{ hours}

We know, \text{Time} = \frac{\text{Distance}}{\text{Speed}}

According to the question,

\frac{6}{9-x}+\frac{6}{x}=\frac{8}{3}

Taking LCM and 6 common

6[\frac{x+9-x}{(9-x)x}]=\frac{8}{3}

Take 6 to another side,

\frac{9}{9x-x^2}=\frac{8}{3\times 6}

Cross multiply,

9\times 18=8\times(9x-x^2)

162=72x-8x^2

Taking 4 common and cancel out

4x^2-36x+81=0

Solve quadratic equation by middle term split,

4x^2-18x-18x+81=0

2x(2x-9)-9(2x-9)=0

(2x-9)(2x-9)=0

\Rightarrow 2x-9=0

\Rightarrow x=\frac{9}{2}=4.5

Therefore, The speed of the river's current is 4.5 km/hr.

You might be interested in
51 more than y is greater than -240
svet-max [94.6K]

Answer:

y + 51 ≥ -240

Step-by-step explanation:

4 0
3 years ago
Read 2 more answers
The product of a number and-5 is-115
kodGreya [7K]
The answer to the question is 23


8 0
3 years ago
Read 2 more answers
- Another way to multiply decimals is to multiply as you would with
oksano4ka [1.4K]
One for 5.8 and one for 1.2
Hope this helps
3 0
3 years ago
4. Where do new genes come from? (1 point)
UNO [17]

Answer:

I hope this helped I reshearsed and did my thinking here a handful help need more help call me at 4076321760

Step-by-step explanation:

How the enormous structural and functional diversity of new genes and proteins was generated (estimated to be 1010–1012 different proteins in all organisms on earth [Choi I-G, Kim S-H. 2006. Evolution of protein structural classes and protein sequence families. Proc Natl Acad Sci 103: 14056–14061] is a central biological question that has a long and rich history. Extensive work during the last 80 years have shown that new genes that play important roles in lineage-specific phenotypes and adaptation can originate through a multitude of different mechanisms, including duplication, lateral gene transfer, gene fusion/fission, and de novo origination. In this review, we focus on two main processes as generators of new functions: evolution of new genes by duplication and divergence of pre-existing genes and de novo gene origination in which a whole protein-coding gene evolves from a noncoding sequence.

How new genes emerge and functionally diversify are very fundamental questions in biology, as new genes provide the raw material for evolutionary innovation that allows organisms to adapt, increase in complexity, and form new species. An organism can acquire new genes through at least three distinct, but potentially overlapping, mechanisms (Fig. 1). Thus, a pre-existing gene can be transferred ready made from another organism by lateral gene transfer (via transformation, transduction, and conjugation), or it can evolve by modification of an already existing gene (by duplication–divergence or gene fusion/fission) or it can be generated de novo from noncoding DNA. It is clear that these mechanisms have generated the diversity of genes and proteins that underlies the existence of all organisms, but their relative importance in new gene evolution and functional diversification is unclear. Thus, their importance will depend on several factors, including the organism and gene studied, the time scales involved (e.g., over recent time scales in the majority of eubacteria lateral gene transfer is a more dominant process than the others), and the methodological problems associated with an unambiguous identification of a gene emerging within an organism (a paralog) or being imported from another organism (a xenolog). In this article, we will focus on the roles of the two latter processes (gene duplication–divergence and de novo origination) as generators of new genes, mainly because they address the basic question of how new genes actually emerge (rather than how functional genes are transferred).

3 0
3 years ago
Solve -5 = 3x - 14.<br> X=__
motikmotik

Answer:

x=3

Step-by-step explanation:

6 0
2 years ago
Read 2 more answers
Other questions:
  • A penny is 0.061 inchthick. wath is the valuee of the 6 in the thickness of a penny
    8·1 answer
  • Ishaan is 3 times as old as Christopher and is also 14 years older than Christopher/10088809/d7a108ae?utm_source=registration
    5·1 answer
  • If the length of a rectangular field is twice the width and the perimeter is 24. Write an equation that an be used to solve for
    13·1 answer
  • Define the variable you will use in your model
    15·1 answer
  • What is the MAD of the number of goals scored which was 24 in 10 games with a mean of 2.4?
    14·1 answer
  • If x + y = 7 and xy = 4, then find the value of x^2 + y^2.
    13·2 answers
  • ANSWER !! <br> ILL GIVE 40 POINTS !!<br> DONT SKIP :(( <br> PLUS BRAINLIEST !
    13·2 answers
  • Noah jumped for 9 mins. what percentage of diegos time is that? (diegos time is 20 mins)
    5·2 answers
  • Brainiest to whoever right
    15·1 answer
  • The scale factor of S to T is 4:1
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!