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
otez555 [7]
3 years ago
15

Suppose that y varies directly with x and y = 10 when x = 20. What is y when x = 15?

Mathematics
1 answer:
aev [14]3 years ago
3 0

Given that,

y varies directly with x and y = 10 when x = 20.

To find,

The value of y when x = 15.

Solution,

y\propto x\\\\y=kx

Put x = 20 and y = 10

k=\dfrac{y}{x}\\\\k=\dfrac{10}{20}\\\\=\dfrac{1}{2}

Put k = 1/2 and x = 15 to find the value of y.

y=\dfrac{1}{2}\times 15\\\\=7.5

So, the value of y is 7.5

You might be interested in
Which of the following can be a solution to the inequality below?<br> 2x &gt; 6.<br> Pls send help
Citrus2011 [14]

Answer:

x>3

Step-by-step explanation:

you divide both sides by 2 then you get three. The sign remains the same.

3 0
3 years ago
A 1000-liter (L) tank contains 500 L of water with a salt concentration of 10 g/L. Water with a salt concentration of 50 g/L flo
djverab [1.8K]

Answer:

a) y(t)=50000-49990e^{\frac{-2t}{25}}

b) 31690.7 g/L

Step-by-step explanation:

By definition, we have that the change rate of salt in the tank is \frac{dy}{dt}=R_{i}-R_{o}, where R_{i} is the rate of salt entering and R_{o} is the rate of salt going outside.

Then we have, R_{i}=80\frac{L}{min}*50\frac{g}{L}=4000\frac{g}{min}, and

R_{o}=40\frac{L}{min}*\frac{y}{500} \frac{g}{L}=\frac{2y}{25}\frac{g}{min}

So we obtain.  \frac{dy}{dt}=4000-\frac{2y}{25}, then

\frac{dy}{dt}+\frac{2y}{25}=4000, and using the integrating factor e^{\int {\frac{2}{25}} \, dt=e^{\frac{2t}{25}, therefore  (\frac{dy }{dt}+\frac{2y}{25}}=4000)e^{\frac{2t}{25}, we get   \frac{d}{dt}(y*e^{\frac{2t}{25}})= 4000 e^{\frac{2t}{25}, after integrating both sides y*e^{\frac{2t}{25}}= 50000 e^{\frac{2t}{25}}+C, therefore y(t)= 50000 +Ce^{\frac{-2t}{25}}, to find C we know that the tank initially contains a salt concentration of 10 g/L, that means the initial conditions y(0)=10, so 10= 50000+Ce^{\frac{-0*2}{25}}

10=50000+C\\C=10-50000=-49990

Finally we can write an expression for the amount of salt in the tank at any time t, it is y(t)=50000-49990e^{\frac{-2t}{25}}

b) The tank will overflow due Rin>Rout, at a rate of 80 L/min-40L/min=40L/min, due we have 500 L to overflow \frac{500L}{40L/min} =\frac{25}{2} min=t, so we can evualuate the expression of a) y(25/2)=50000-49990e^{\frac{-2}{25}\frac{25}{2}}=50000-49990e^{-1}=31690.7, is the salt concentration when the tank overflows

4 0
3 years ago
There are 4 times as many monkeys as elephants at the zoo. If the totAl number of monkeys and elephants is 35, how many monkeys
Tanya [424]
Let's call the number of elephants x.
x+4x=35
5x=35
x=7
So there are 7 elephants. There are four times as many monkeys.
7×4=28
There are 28 monkeys.
8 0
3 years ago
Read 2 more answers
Plot the point (4, −3). Start at the origin. Move 4 units . Move 3 units . The point is at .
Naily [24]

Answer:

the point is D

Step-by-step explanation:

brainliest plz

7 0
2 years ago
Read 2 more answers
Solve: -3/4x - 8 + 5/4x - 4 = 9 x=?​
ExtremeBDS [4]

Answer: x=42

Step-by-step explanation: In the picture

8 0
3 years ago
Other questions:
  • Last weekend, Lexie spent 1/2 of her money on the movies and 1/4 of her money on food. She has $7.50 remaining. How much money d
    14·1 answer
  • HELP!!!!!!!!!! 19POINTS!!!!!!!!!!!!!!!!!!
    6·1 answer
  • Slopes of parallel and perpendicular lines
    8·1 answer
  • What is the GCF for 24 and 60
    9·1 answer
  • 6x^5y^2z^3+ 10x^3yz^7 -20x^4z^3
    12·1 answer
  • 12,354,897 place each # in place value 245897just need to make sure I am right ...okay 2 =1million,4=1thousand,5=10 thousand,8=1
    5·1 answer
  • What is 4x – 97 + 12 – x = -80.5
    11·2 answers
  • Do y’all know the answer to this!?
    8·1 answer
  • A sweater costs $36. If the sweater is 35% off how much is the total?
    12·2 answers
  • Lea sold half of her comic books and then bought thirteen more. She now has 42.
    6·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!