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3 years ago

HELP PLEASE I AM TIMED PLZZZZ!!!!!!!!!!!!!

Mathematics

1 answer:

steposvetlana [31]3 years ago

7 0

Answer: t = 34

Step-by-step explanation:

Since 15 was multiplied by two to get 30 as the denominator, you would multiply 17 by 2 therefore getting 34 = t.

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At 2 PM, a thermometer reading 80°F is taken outside where the air temperature is 20°F. At 2:03 PM, the temperature reading yiel

Alexeev081 [22]

Use Law of Cooling:
$T(t) = (T_0 - T_A)e^{-kt} +T_A$
T0 = initial temperature, TA = ambient or final temperature

First solve for k using given info, T(3) = 42
$42 = (80-20)e^{-3k} +20 \\ \\ e^{-3k} = \frac{22}{60}=\frac{11}{30} \\ \\ k = -\frac{1}{3} ln (\frac{11}{30})$

Substituting k back into cooling equation gives:
$T(t) = 60(\frac{11}{30})^{t/3} + 20$

At some time "t", it is brought back inside at temperature "x".
We know that temperature goes back up to 71 at 2:10 so the time it is inside is 10-t, where t is time that it had been outside.
The new cooling equation for when its back inside is:
$T(t) = (x-80)(\frac{11}{30})^{t/3} + 80 \\ \\ 71 = (x-80)(\frac{11}{30})^{\frac{10-t}{3}} + 80$
Solve for x:
$x = -9(\frac{11}{30})^{\frac{t-10}{3}} + 80$
Sub back into original cooling equation, x = T(t)
$-9(\frac{11}{30})^{\frac{t-10}{3}} + 80 = 60 (\frac{11}{30})^{t/3} +20$
Solve for t:
$60 (\frac{11}{30})^{t/3} +9(\frac{11}{30})^{\frac{-10}{3}}(\frac{11}{30})^{t/3} = 60 \\ \\ (\frac{11}{30})^{t/3} = \frac{60}{60+9(\frac{11}{30})^{\frac{-10}{3}}} \\ \\ \\ t = 3(\frac{ln(\frac{60}{60+9(\frac{11}{30})^{\frac{-10}{3}}})}{ln (\frac{11}{30})}) \\ \\ \\ t = 4.959$

This means the exact time it was brought indoors was about 2.5 seconds before 2:05 PM

8 0

4 years ago

Find the base of a parallelogram if the area is 90 and the ratio of base to altitude is 5:2

Nutka1998 [239]

Area of a Parallelogram = b * h

Total Number of unit ratio = 5+2 = 7

Value of 1 unit = 90/7 = 12.857

Base of the Parallelogram = 12.857 * 5 = 64.285

In short, Your Answer would be: 64.285

Hope this helps!

8 0

3 years ago

Read 2 more answers

5. Write 895,003,049 in expanded form.

aleksandr82 [10.1K]

Answer:

800,000,000 90,000,000 5,000,000 3,000 40 9

Step-by-step explanation:

8 0

4 years ago

Read 2 more answers

The sum of 2 numbers is 52. Express the product of the numbers, P, as a function of one of the numbers, x.

kolezko [41]

Answer:

The sum of 2 numbers is 52. Express the product of the numbers, P, as a function of one of the numbers, x.

the answer is p(x) = -x² + 52x

Step-by-step explanation:

let the two numbers be x and y

the sum of the two numbers = x + y

≡ x + y = 52

make y the subject of equation

y= 52 - x

to express the product of the numbers, P, as a function of one of the numbers, x. implies that

P(x) = x(-x + 52)

finally,

p(x) = -x² + 52x

8 0

3 years ago

Solve the following variation problem.

julia-pushkina [17]

From the calculation done below, the interest when the rate is 9% is $101.25.

<h3>How interest is calculated using direct variation?</h3>

Since the interest on investment varies directly as the rate of interest, the relevant direct variation formula to use to calculate investment is as follows:

i = kr ................................. (1)

Where:

i = interest amount = $45

k = investment = ?

r = interest rate = 0.04

Substituting the values into equation (1) and solving for k, we have:

45 = k0.04

k = 45 / 0.04

k = $1,125

To find the interest when the rate is 9%, we substitute k = $1,125 and r = 9% into equation (1) as follows:

i = $1,125 * 9% = $101.25

Learn more about interest here: brainly.com/question/26457073.

#SPJ1

8 0

2 years ago