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antiseptic1488 [7]
2 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)
Mathematics
1 answer:
TiliK225 [7]2 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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A teacher wants to see if a new unit on factoring is helping students learn. She has five randomly selected students take a pre-
sergiy2304 [10]

Answer:

The <em>t</em>-value used for the 95% confidence interval of paired data is 2.776.

Step-by-step explanation:

The confidence interval formula for mean difference for a paired data is as follows:

CI=\bar x_{d}\pm t_{\alpha/2, (n-1)}\times \frac{s_{d}}{\sqrt{n}}

Here,

\bar x_{d} = sample mean of the difference,

s_{d} = sample standard deviation of the difference,

<em>n </em>= sample size (both samples are of same size).

t_{\alpha/2, (n-1)} = critical value of <em>t</em>

(<em>n</em> - 1) = degrees of freedom

The information provided is:

<em>n</em> = 5

Confidence level = 95%

The critical value of <em>t</em> is:

t_{\alpha/2, (n-1)}=t_{0.05/2, (5-1)}

               =t_{0.025, 4}

               =2.776

*Use a <em>t</em>-table for the critical value of <em>t</em>.

Thus, the <em>t</em>-value used for the 95% confidence interval of paired data is 2.776.

4 0
2 years ago
A pair of boots marked for $25 was sold at $15. What was the
patriot [66]

Answer:

40%

Step-by-step explanation:

Original price: $25

Discounted price: $15

Amount of discount: $25 - $15 = $10

The boots sold for $10 less than the original price.

To find the percent discount, we need to find what percent of $25 is $10.

percent = part/whole * 100%

percent = 10/25 * 100%

percent = 0.4 * 100%

percent = 40%

5 0
2 years ago
27 thousands 3 hundreds 5 ones X 10
Leokris [45]
27 thousand 27,000
3 hundred         300
5 ones                5
27,305 x 10= 273,050 
Please let me know if you have any questions id be happy to explain in more detail
8 0
2 years ago
Read 3 more answers
Each square on the grid is 1 unit by 1 unit. You want to walk from point A to point B via a path that is 7 units long, but you h
Effectus [21]

Answer:

If you are <u>traversing squares</u> then 7 different paths can be taken

If you are <u>traversing edges </u> then 36 different paths can be taken

Step-by-step explanation:

I have attached a picture that would describe the grid which is 7 units long.

The solution to the general problem is if you have to take X right steps, and Y down steps then the number of routes is simply the ways of choosing where to take the down (or right) steps. Such that:

\left (\ {X+Y} \atop {X}} \right.\left)=\left (\ {X+Y} \atop {Y}} \right.\left)

Basically its the combination of terms.

In this problem,

If you are <u>traversing squares</u> then there are 6 right steps and 1 down step,

7 C 1 = 7 C 6= 7

If you are <u>traversing edges </u> then there are 7 right steps and 2 down steps:

9 C 2 = 9 C 7=  36

3 0
2 years ago
The CPI basket price for two consecutive years of five different economies are given. Determine the rate of Inflation for each e
kaheart [24]

Answer:

The inglation rate can be calculated as:

R = ((year2 - year1)/year1 )*100%

A)

Year 1 = $132.00

Year 2 = $134.50

R = (($134.50 - $132.00)/$132.00)*100% = 1.89%

B)

Year 1 = $95.00

Year 2 = $97.50

R = (($97.50 - $95.00 )/$95.00 )*100% = 2.6%

C)

 Year 1 = $100.00

 Year 2 = $102.00

R = (($102.00 - $100.00 )/$100.00 )*100% = 2%

D)

Year 1 = $88.00

Year 2 = $89.25

R = (($89.25 - $88.00 )/$88.00 )*100% = 1.4%

E)

Year 1 = $115.50

Year 2 = $117.50

R = (($117.50 - $115.50 )/$115.50 )*100% = 1.7%

Then the order from least to greatest is:

D, E, A, C, B

8 0
2 years ago
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