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antiseptic1488 [7]

3 years ago

9

The radioisotope Mo-91 has a t1/2 of 15.5min. A sample decays at the rate of 954counts/min (954cpm). After how many minutes will

the decay be at 7.45cpm? (Step by step please)

1 answer:

TiliK225 [7]3 years ago

5 0

Step-by-step explanation:

Transcribed image text: Spectra Analysis 7 100 80 60 40 20 150 50 STRUCTURE 60 40 20 0 180 160 140 120 100 8O

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The value of 9−y is twice the value of y. What is the value of y?

ElenaW [278]

Answer:

y = 3

Step-by-step explanation:

9 - y = 2y

<u>Step 1: Add y to both sides</u>

9 - y + y = 2y + y

9 = 3y

<u>Step 2: Divide both sides by 3</u>

9 / 3 = 3y / 3

3 = y

Answer: y = 3

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Express sin Q as a fraction in simplest terms.

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Answer:

Solution given

Sin Q=opposite/hypotenuse=28/29

<u>28/29</u><u> </u><u>is</u><u>. </u><u>a</u><u> </u><u>required</u><u> </u><u>answer</u><u>.</u><u />

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3 years ago

Find the radian measure of the central angle of a circle of radius r that intercepts an arc of length s radius r 35 kilometers a

weeeeeb [17]

Answer:

Step-by-step explanation:

s=rtheta

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3 years ago

Use technology or a z-score table to answer the question.

Alik [6]

Answer:

The second choice: Approximately $65.2\%$ of the pretzel bags here will contain between 225 and 245 pretzels.

Step-by-step explanation:

This explanation uses a z-score table where each $z$ entry has two decimal places.

Let $\mu$ represent the mean of a normal distribution of variable $X$ . Let $\sigma$ be the standard deviation of the distribution. The z-score for the observation $x$ would be:

$\displaystyle z = \frac{x - \mu}{\sigma}$ .

In this question,

$\mu = 240$ .
$\sigma = 9.3$ .

Calculate the z-score for $x_1 = 225$ and $x_2 = 245$ . Keep in mind that each entry in the z-score table here has two decimal places. Hence, round the results below so that each contains at least two decimal places.

$\begin{aligned} z_1 &= \frac{x_1 - \mu}{\sigma} \\ &= \frac{225 - 240}{9.3} \approx -1.61\end{aligned}$ .

$\begin{aligned} z_2 &= \frac{x_2 - \mu}{\sigma} \\ &= \frac{245 - 240}{9.3} \approx 0.54\end{aligned}$ .

The question is asking for the probability $P(225 \le X \le 245)$ (where $X$ is between two values.) In this case, that's the same as $P(-1.61 \le Z \le 0.54)$ .

Keep in mind that the probabilities on many z-table correspond to probability of $P(Z \le z)$ (where $Z$ is no greater than one value.) Therefore, apply the identity $P(z_1 \le Z \le z_2) = P(Z \le z_2) - P(Z \le z_1)$ to rewrite $P(-1.61 \le Z \le 0.54)$ as the difference between two probabilities:

$P(-1.61 \le Z \le 0.54) = P(Z \le 0.54) - P(Z \le -1.61)$ .

Look up the z-table for $P(Z \le 0.54)$ and $P(Z \le -1.61)$ :

$P(Z \le 0.54)\approx 0.70540$ .
$P(Z \le -1.61) \approx 0.05370$ .

$\begin{aligned}& P(225 \le X \le 245) \\ &= P\left(\frac{225 - 240}{9.3} \le Z \le \frac{245 - 240}{9.3}\right)\\&\approx P(-1.61 \le Z \le 0.54) \\ &= P(Z \le 0.54) - P(Z \le -1.61)\\ &\approx 0.70540 - 0.05370 \\& \approx 0.65.2 \\ &= 65.2\% \end{aligned}$ .

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3 years ago

How do you find a rate of a number

KATRIN_1 [288]

To determine the rate of a number do the following steps:

Multiply the number by the percent (e.g. 87 * 68 = 5916)

Divide the answer by 100 (Move decimal point two places to the left) (e.g. 5916/100 = 59.16)

Round to the desired precision (e.g. 59.16 rounded to the nearest whole number = 59)

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3 years ago

Read 2 more answers