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Salsk061 [2.6K]
3 years ago
9

The half-life of a certain substance is 20 years. How much of a 100 gram sample will be left after 20 years?

Mathematics
2 answers:
Dahasolnce [82]3 years ago
7 0

50 grams of that sample will be left after 20 years since it’s only gone through one half-life exactly.

cluponka [151]3 years ago
5 0

\bf \textit{Amount for Exponential Decay using Half-Life} \\\\ A=P\left( \frac{1}{2} \right)^{\frac{t}{h}}\qquad \begin{cases} A=\textit{accumulated amount}\\ P=\textit{initial amount}\dotfill &100\\ t=\textit{elapsed time}\dotfill &20\\ h=\textit{half-life}\dotfill &20 \end{cases} \\\\\\ A=100\left( \frac{1}{2} \right)^{\frac{20}{20}}\implies A=100\left( \frac{1}{2} \right)^1\implies A=50

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Point S is on line segment \overline{RT}
Semenov [28]

Answer:

RT = 20

Step-by-step explanation:

Point S is on line segment

R------------S------------T

RS + ST = RT

Given

ST=3x-8

RT=4x

RS=4x-7,

Step 1

We find x

4x - 7 + 3x - 8 = 4x

4x + 3x -7 - 8 = 4x

7x - 15 = 4x

7x - 4x = 15

3x = 15

x = 15/3

x = 5

Step 2

We find RT

RT = 4x

x = 5

RT = 4 × 5

RT = 20

The numerical length of RT is 20

3 0
3 years ago
The local supermarket buys lettuce each day to ensure really fresh produce. Each morning any lettuce that is left from the previ
jekas [21]

Given Information:

Cost price = $4

Selling price = $10

Salvage value = $1.50

Average demand = μ = 250 boxes

Standard deviation = σ = 34 boxes

Required Information:

Number of lettuce boxes = ?

Answer:

The supermarket should purchase 268 boxes  of lettuce

Step-by-step explanation:

The required number of lettuce boxes that supermarket should purchase is given by

Number of lettuce boxes = μ + (z*σ)

Where μ is the average demand of lettuce boxes, σ is the standard deviation, and z is the z-score which is given by

p = C_us/(C_us + C_os)

The z-score corresponding to probability p will be obtained.

The cost of under stocking is given by

C_us = Selling price - Cost price

C_us = $10 - $4

C_us = $6

The cost of over stocking is given by

C_os = Cost price - Salvage value

C_os = $4 - $1.50

C_os = $2.50

p = C_us/(C_us + C_os)

p = 6/(6 + 2.50)

p = 0.7058

p  = 70.58%

The z-score corresponding to 70.58% probability is approximately 0.54

Number of lettuce boxes = μ + (z*σ)

Number of lettuce boxes = 250 + (0.54*34)

Number of lettuce boxes = 250 + (18.36)

Number of lettuce boxes = 268.36

Number of lettuce boxes ≈ 268

Therefore, the supermarket should purchase 268 boxes of lettuce.

How to use z-table?

Step 1:

In the z-table, find the probability you are looking for and note down the two-digit number of the given row. (e.g 0.5, 2.2, 0.5 etc.)

Step 2:

Then look up at the top of z-table and note down the value in the column for the remaining decimal point in the range of 0.00 to 0.09.

Step 3:

Finally, add the numbers obtained from step 1 and step 2.

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4 years ago
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3400000 in scientific notation
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3 years ago
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Katena32 [7]

Answer:

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6 0
3 years ago
Solve for y. -3/y=6 Simplify your answer as much as possible.
Molodets [167]
Solving for "y" means that we need to get y to be on one side of the equation. It should look like y= something. To get the y by itself, we need to get rid of that -3. To do that, we'll have to divide by -3 (because even though there's a y being divided, the -3 is still the numerator). 6/-3 is -1/2. Therefore your answer is y=-1/2

<em>Don't forget to rate this answer the Brainliest!</em>
7 0
3 years ago
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