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swat32
3 years ago
5

A radioactive substance decays exponentially. A scientist begins with 190 milligrams of a radioactive

Mathematics
1 answer:
worty [1.4K]3 years ago
6 0

Answer: 65.1 (mg)

Step-by-step explanation:

y=190*e^{-a*t}\\\\Calculate\ a:\\\\t=33,y=95(mg)\\\\190*e^{-a*33}=95\\\\e^{-a*33}=0.5\\\\-a*33=ln(0.5)\\\\a=\dfrac{ln(\dfrac{1}{2}) }{-33} \\\\a=0,02100... \approx{0.021}\\\\If\ t=51\ h, y=190*e^{-0.02100*51}=65.09167...\approx{65.1}

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A line segment is 20 units long. The line segment is translated up 6 units and left 8 units. The length of the resulting line se
lapo4ka [179]

Answer:

The length of the resulting line segment is 20 units and the length of a line segment is preserved on translation.

Step-by-step explanation:

The given length of the line segment is 20 units.

The line segment is translated up 6 units and left 8 units.

Here, the line segment is translated, so the whole line segment is at a new position after translation, there is no change in the length of the line.

So, the length of the line segment is preserved on translation.

After translation, the length of the line remains unchanged.

So, the length of the resulting line segment is 20 units.

3 0
4 years ago
In a normal respiratory cycle the volume of air that moves into and out of the lungs is about 498 mL. The reserve and residual v
Lisa [10]

Answer:

The model is V(t)=2239+249\sin(\frac{\pi}{2}t).

Step-by-step explanation:

Consider the given information.

The volume of air inside the lungs increases or decreases so for this we will use the basic sine function B(t)=d+a\sin[b(t+ \frac{c}{a})] as our parent function.

Let us assume that the phase shift is 0 it means \frac{c}{b}=0.

The air that moves into and out of the lungs is about 498 mL.

It means the amplitude of the function will vary by 249(half of 498).

The reserve and residual volumes of air that remains in the lungs occupy about 1990 mL which is the minimum air in the lungs.

So, the max air will be: 1990+498 =2488 mL

And the average will be d=1990+249=2239 ml

The horizontal stretch will be  b=\frac{2\pi}{4}=\frac{\pi}{2} as we know that period of y=\sin t is 2\pi and respiratory cycle for an average human takes about 4 seconds.

Hence, the model is V(t)=2239+249\sin(\frac{\pi}{2}t).

7 0
3 years ago
Sammy bought shoes that cost
lara [203]

Before sales tax he would have to pay $40 * (1 - 0.25) + $100 * (1 - 0.35) = $30 + $65 = $95.

With a 6% sales tax he'd have to pay 1.06 * $95 = $100.70.

i hope this helps! :D

5 0
3 years ago
If I add 2 tablespoons of sugar to each cup of coffee, what is the ratio of sugar to coffee?
Gemiola [76]
For any amount of pure Coffee (no milk), you can put 39 grams of sugar or nearly 10 teaspoons of sugar, as Coffee has no sugar in it. 30ml is a standard espresso size so to be equivalent per ml of liquid you would need to put 3.1 grams of sugar which is less than a teaspoon.
5 0
3 years ago
Read 2 more answers
The function f(x) = 3,005(1 + 0.03)x represents the amount of money in a savings account where x represents time in years. What
Damm [24]

Answer:

Principal or Initial Amount of Money

Step-by-step explanation:

Given, f(x) = 3005(1+0.03)^x.  

Now, comparing with f(x)= ab^x where  

a = initial value

b = rate of growth

x = time or period  

This, function is an exponential growth function. So by comparing we get a= 3005 which is the initial value b = 0.03.  

But in this case according to the question, the function f(x)= 3005(1+0.03)^x represents the amount of money in a savings. So the answer is 3005 which is the initial money.

7 0
3 years ago
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