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kiruha [24]
3 years ago
12

An atom of a certain element has 21 protons, 21

Mathematics
1 answer:
Lorico [155]3 years ago
3 0
45-21=24 neutrons :)

As the generally accepted mass of an electron is 0. So, to find the mass of neutrons, minus the protons from the total mass.
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Ruth invested in a lifetime annuity that begins payments at age 65. Her life
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Answer:5053.71

Step-by-step explanation:

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3 years ago
In order to estimate the average time spent per student on the computer terminals at a local university, data were collected for
tatuchka [14]

Answer:

With a .95 probability, the margin of error is = 0.392

Step-by-step explanation:

Given -

In order to estimate the average time spent per student on the computer terminals at a local university, data were collected for a sample of 81 business students over a one-week period.

Sample size ( n ) =81

Standard deviation (\sigma ) = 1.8 hours

\alpha = 1 -.95 =.05

Z_{\frac{\alpha }{2}} = Z_{\frac{.05 }{2}} = 1.96           (Using Z table)

With a .95 probability, the margin of error is

Margin of error  =  Z_{\frac{\alpha }{2}}\frac{\sigma }{\sqrt{n}}

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8 0
3 years ago
A rectangular box is 6 inches wide 10 inches long and 2 inches tall how much wrapping paper is needed to cover the box exactly
stepladder [879]

Answer:

184 in²

Step-by-step explanation:

Given :

Width, w = 6 inches

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Surface area = 2(lw + lh + wh)

Surface area = 2((6*10) + (6*2) + (10*2))

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7 0
3 years ago
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Write 2 equations:

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Now replace a with 22 in the first equation and solve for b:

22 + b = 39

b = 39 -22

b = 17

The two numbers are 17 and 22.

8 0
4 years ago
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Which expression are equivalent to 3p + 15? choose ALL THAT APPLY
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The equivalent expressions are: A and C
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3 years ago
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