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kotykmax [81]
3 years ago
15

Cesium chloride is a radioactive substance that is sometimes used in cancer treatments. Cesium chloride has a biological half-li

fe of 4 months. (Note: Use the concepts of half-life or doubling time. The biological half-life of a substance is the amount of time it takes for the physiologic or radiologic activity of that substance to reduce by half.)
Required:
a. Find a model for the amount of cesium chloride left in the body x months after 840 mg has been injected.
b. How long will it take for the level of cesium chloride to fall below 3%?
Mathematics
2 answers:
Natalka [10]3 years ago
5 0

Step-by-step explanation:

my workings and answers is in the image above

zepelin [54]3 years ago
3 0

Answer:

There is another approach to this problem that

might be more in line with what you are studying ..... NOTE: the first answer is correct.

Step-by-step explanation:

1 = 2x^{4}

1/2 = x^{4}

ln(1/2) = 4 ln(x)

ln(1/2)/4 = ln(x)

x = e^{-0.1732}

x = .8408

~~~~~~~~~~~~~~~~

model : 840(0.8408)^{t}

~~~~~~~~~~~~~~~~~

(.03* 840)  = 840(0.8408)^{t}

(.25.2)  = 840(0.8408)^{t}

.03 = (0.8408)^{t}

ln(.03 )=ln( (0.8408)^{t})

t = ln(.03 )/ln(0.8408 )

t = 20.22

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Suppose that X is a random variable with mean 30 and standard deviation 10. Also suppose that Y is a random variable with mean 2
Bas_tet [7]
Part a: For variable X using z score you have (x-30)/10, replace X for this expression in (a), i mean Z=2+10((x-30)/10) = 2+x-30= put this in the way of z score = (x-18)/1, so the mean is 18 and standard deviation is 1.
Part b: Z=X+Y= (x-30)/10 + (x-20)/8 = solve adding fractions = (18x-440)/80 now divide all the numbers between 18 (because you need to show as z score way) = (x-24.4)/4.4, so the mean is 24.4 and standard deviation is 4.4.
For part c,do the same.
3 0
3 years ago
1. find the product and write it in simplest form: 1 1/3 x 3/8 =
I am Lyosha [343]

Answer:

The answer to number 1 is A.

Step-by-step explanation:

To find this answer, I made 1 1/3 into one big fraction. I multiplied the denominator by the whole number (3x1) and then added that product to the numerator. (3+1). The new fraction is now 4/3 (you keep the denominator the same). The next step is to multiply 4/3 by 3/8. When multiplying fractions, you multiply straight across (the numerator by the numerator, and the denominator by the denominator). Your answer is now 12/24. The final step is to simplify the answer. Since 12 is half of 24, the answer is 1/2.

3 0
3 years ago
What is another way to represent the ratio 40:1?
Shtirlitz [24]
40/1 is the other way
7 0
4 years ago
Percent increase from 6 to 10.50
borishaifa [10]
10,50 - 6,00 = 4,50

6............100%
4,50..........x

6x = 450
x = 450/6
x = 75%
3 0
4 years ago
Determine if y varies directly with x. Give the constant of variation, when appropriate. (picture below)
maxonik [38]

Based on the given variation, y does not vary directly with x and the constant of variation are 8, 3.2 and 1.25 respectively.

<h3>Variation</h3>

y = k × x

where,

k = constant of proportionality

y = -40

x = -5

y = k × x

-40 = k × -5

-40 = -5k

k = -40/-5

k = 8

when,

y = 8 and x = 2.5

y = k × x

8 = k × 2.5

8 = 2.5k

k = 8/2.5

k = 3.2

when,

y = 5 and x = 4

y = k × x

5 = k × 4

5 = 4k

k = 5/4

k = 1.25

Learn more about variation:

brainly.com/question/6499629

#SPJ1

5 0
2 years ago
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