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2 years ago

Ill mark brainliest helpp plzzz also its more than one answer!!

Mathematics

1 answer:

balandron [24]2 years ago

5 0

Answer:

a) ( j + m ) / 7

b) The product of j and m increased by 7

Step-by-step explanation:

You might be interested in

A random sample of 40 college students has a mean earnings of $3120 over the summer months. Assume the population standard devi

PSYCHO15rus [73]

Answer:

A normal distribution or z-test is used to construct a confidence interval.

Step-by-step explanation:

We are given the following in the question:

Sample mean, $\bar{x}$ = $3120

Sample size, n = 40

Population standard deviation, σ = $677

The distribution of earnings of college is a normal distribution.

Conditions:

Since we are given the population standard deviation and the the sample size is also greater than 30.

Conclusion:

Thus, we use a normal distribution or z-test to construct a confidence interval.

4 0

3 years ago

Suppose that a spherical droplet of liquid evaporates at a rate that is proportional to its surface area: where V = volume (mm3

Alex

Answer:

V = 20.2969 mm^3 @ t = 10

r = 1.692 mm @ t = 10

Step-by-step explanation:

The solution to the first order ordinary differential equation:

$\frac{dV}{dt} = -kA$

Using Euler's method

$\frac{dVi}{dt} = -k *4pi*r^2_{i} = -k *4pi*(\frac {3 V_{i} }{4pi})^(2/3)\\ V_{i+1} = V'_{i} *h + V_{i} \\$

Where initial droplet volume is:

$V(0) = \frac{4pi}{3} * r(0)^3 = \frac{4pi}{3} * 2.5^3 = 65.45 mm^3$

Hence, the iterative solution will be as next:

i = 1, ti = 0, Vi = 65.45

$V'_{i} = -k *4pi*(\frac{3*65.45}{4pi})^(2/3) = -6.283\\V_{i+1} = 65.45-6.283*0.25 = 63.88$

i = 2, ti = 0.5, Vi = 63.88

$V'_{i} = -k *4pi*(\frac{3*63.88}{4pi})^(2/3) = -6.182\\V_{i+1} = 63.88-6.182*0.25 = 62.33$

i = 3, ti = 1, Vi = 62.33

$V'_{i} = -k *4pi*(\frac{3*62.33}{4pi})^(2/3) = -6.082\\V_{i+1} = 62.33-6.082*0.25 = 60.813$

We compute the next iterations in MATLAB (see attachment)

Volume @ t = 10 is = 20.2969

The droplet radius at t=10 mins

$r(10) = (\frac{3*20.2969}{4pi})^(2/3) = 1.692 mm\\$

The average change of droplet radius with time is:

Δr/Δt = $\frac{r(10) - r(0)}{10-0} = \frac{1.692 - 2.5}{10} = -0.0808 mm/min$

The value of the evaporation rate is close the value of k = 0.08 mm/min

Hence, the results are accurate and consistent!

5 0

3 years ago

When a water-cooled nuclear power plant is in operation, oxygen in the water is transmuted to nitrogen-17. After the reactor is

wolverine [178]

Answer:

The differential equation is $\frac{dR}{dt} = -kR$

Step-by-step explanation:

Differential equation for the rate of change in radiation level:

Radiation level is R.

Rate of change indicates that the radiation level R varies in function of time t, which mathematically means that we have:

$\frac{dR}{dt}$

After the reactor is shut down, the radiation from the nitrogen-17 decreases in such a way that the rate of change in the radiation level is directly proportional to the radiation level.

Rate of change is k. Decreases means that k is negative. Proportional to the radiation level of R means that -k multiplies R. So the differential equation is:

$\frac{dR}{dt} = -kR$

7 0

2 years ago

Jessica wants to plan where she will place furniture in her room, so she has drawn a scale model of her room in order to begin p

Setler79 [48]

To solve this problem you must apply the proccedure shown below:
1. You have that:
 - The scale model is 11 inches long and 8.5 inches wide.
- The door to her room takes up 1.75 inches.
- The longest wall in Jessica’s actual room is 15 feet long.
2. Therefore, the actual size of the door is:
15 feet=180 inches
1.75 inches(180 inches/11 inches)=28.63 inches
3. If the door in completely open, you must apply the formula for calculate the area of a semicircle:
A=πr²/2
r=28.63 inches
A=π(28.63 inches)²/2
A=1288.11 inches²
The answer is: 1288.11 inches²

5 0

2 years ago

Which graph can be used to find the solution(s) to x2-4x+4=2x+1+x2?

Damm [24]

The answer is x=1/2 or 0.5

4 0

2 years ago

Read 2 more answers