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
elixir [45]
3 years ago
6

A boat travels 2km upstream and 2km downstream. The total time of the trip is 1 hour. The speed of the stream is 2km/h. What is

the speed of the boat in still water?
Mathematics
1 answer:
scoray [572]3 years ago
7 0
2 = ( v + 2 ) × t1 ;
2 = ( v - 2 ) × t2 ;
t1 + t2 = 1 ;
where v is the speed of the boat in still water ; t1 is the time upstream ; t2 is the tome downstream ;
Then, v + 2 = 2 / t1 and v - 2 = 2 / t2 ;
v = 2 / t1   -  2  and v = 2 / t2  +  2 ;
2 / t1 - 2 = 2 / t2 + 2 ;
2 / t1 - 2 / t2 = 4 ;
1 / t1 - 1 / t2 = 2 ;
t2 - t1 = 2t1t2 ;
But, t2 = 1 - t1 ;
1 - t1 - t1 = 2t1( 1 - t1 ) ;
1 - 2t1 = 2t1 - 2t1^2 ;
2t1^2 - 4t1 + 1 = 0 ; quadratic equation ;
solving this equation , 
t1 ≈ 0.29 hour ;
v ≈ 2 / 0.29 - 2;
v ≈ 4.89 km/h ;

You might be interested in
A shoe store donated a percent of every sale to hospitals. The total sales were ​$6,060 so the store donated ​$303. What percent
lesya692 [45]

Answer:

5%

Step-by-step explanation:

303 = 6060p

303/6060 = p

.05 = p

5 0
3 years ago
PLEASE HELP ASAP I’LL MARK BRAINLIEST Find the area of the figure.
Sonbull [250]
Area of a semicircle is 1/2* πr^2
Area of a square is s^2


Square’s area: 4mm^2

The radius is 3mm
Plug into the equation

1/2* π(3^2)
1/2* π(9)

We can use 3.14 as an estimate of pi

1/2*28.26

14.13mm^2

Now just add them both

Total area 18.13mm^2
4 0
3 years ago
Which is the slope of a line perpendicular to the line whose equation is y=2x+5?
Black_prince [1.1K]

Answer:

-1/2

Step-by-step explanation:

the slope of a line that is perpendicular to a given equation of a line, is the negative reciprocal of the original slope

8 0
3 years ago
Read 2 more answers
Help me please will mark as brainliest
julsineya [31]
Option D should be the right answer
5 0
3 years ago
Find the radius of the circle with equation x²+y²+8x+8y+28=0
galina1969 [7]
<h2>Hello!</h2>

The answer is:

Center: (-4,-4)

Radius: 2 units.

<h2>Why?</h2>

To solve the problem, using the given formula of a circle, we need to find its standard equation form which is equal to:

(x-h)^{2}+(y-k)^{2}=r^{2}

Where:

"h" and "k" are the coordinates of the center of the circle and "r" is its radius.

So, we need to complete the square for both variable "x" and "y".

The given equation is:

x^{2}+y^{2}+8x+8y+28=0

So, solving we have:

x^{2}+y^{2}+8x+8y=-28

(x^2+8x+(\frac{8}{2})^{2})+(y^2+8y+(\frac{8}{2})^{2})=-28+((\frac{8}{2})^{2})++(\frac{8}{2})^{2})\\\\(x^2+8x+16 )+(y^2+8y+16)=-28+16+16\\\\(x^2+4)+(y^2+4)=4

(x^2-(-4))+(y^2-(-4))=4

Now, we have that:

h=-4\\k=-4\\r=\sqrt{4}=2

So,

Center: (-4,-4)

Radius: 2 units.

Have a nice day!

Note: I have attached a picture for better understanding.

3 0
3 years ago
Other questions:
  • a recipe for quinoa calls for 2 2/3 cups of milk. conner wants to make 4 batches of quinoa. how much milk does he need?
    5·1 answer
  • you forget the last two digits of your password for a website. A what is the probability that you randomly choose the correct di
    5·1 answer
  • In the function y = 10.00x + 35, y represents the cost of cabin lodging per occupant and x represents the number of occupants. H
    9·1 answer
  • 25 mi/h ≈ ______ ft/s
    5·1 answer
  • You get a part-time job earning $8.60/hr. Tips are $3.25/hr on average. Deductions are FICA (7.65%), federal tax withholding (11
    5·1 answer
  • The expression 100n2 – 1 is equivalent to
    15·1 answer
  • Angela arrives at the mouse thearter at 7:48 p.m. she leaves at 9:50 a.m. how many minutos was she at school.
    8·2 answers
  • The diameters of ball bearings are distributed normally. The mean diameter is 130 millimeters and the variance is 9. Find the pr
    5·1 answer
  • 8(–5m–4)?<br><br><br> a<br> n<br> s<br> w<br> e<br> r
    12·2 answers
  • Verizon has a special and is selling the new IPhone 7 for $299 to new customers. If the Apple Store is charging twice as much as
    15·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!