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Delvig [45]
2 years ago
8

If 3.0 grams of strontium-90 in a rock sample remained in 1989, approximately how many grams of strontium-90 were present in the

original rock sample in 1933?
Mathematics
1 answer:
kirill [66]2 years ago
5 0

Answer:

<em>11.29 grams </em><em>of strontium-90 were present in the original rock sample in 1933.</em>

Step-by-step explanation:

Strontium has a half-life of 28.8 years. Therefore,

1989 - 1933 = 56 years.

56 / 28.8 = 1.94 half-lives

Thus, the quantity of the radioisotope remaining will double for each half-life elapsed. moving backwards in time.

Therefore, moving backwards in time by 1.94 half-lives, the quantity remaining will double by 1.94 times.

Thus, the amount remaining in 1933 is

3.0 × (1.94)² = <em>11.29 grams</em>

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The entire universe of computer games are made up of:
expeople1 [14]

Answer:

Math properties the programmer had put into the software. The majority of programming software is based in math.

Step-by-step explanation:

The other 3 possible answers make no sense.

1. Pixels with red, green, and blue switches - Seriously???

2. Code randomly created by programmers - Seriously???

3. The fundamental properties of physics which consist of numbers and constants (numbers and constants are the same thing and physics has virtually nothing to do with programming)

4 0
2 years ago
The mean weight of newborn infants at a community hospital is 6.6 pounds. A sample of seven infants is randomly selected and the
Lera25 [3.4K]

Answer:

The correct option is  A

Step-by-step explanation:

From the question we are told that

    The  population is  \mu  =  6.6

     The level of significance is \alpha  =  5\%  = 0.05

      The sample data is  9.0, 7.3, 6.0, 8.8, 6.8, 8.4, and 6.6 pounds

The Null hypothesis is H_o  :  \mu =  6.6

 The Alternative hypothesis is  H_a :  \mu  > 6.6

The critical value of the level of significance obtained from the normal distribution table is

                       Z_{\alpha } = Z_{0.05 } = 1.645

Generally the sample mean is mathematically evaluated as

      \=x =  \frac{\sum x_i }{n}

substituting values

      \=x =  \frac{9.0 +  7.3 +  6.0+ 8.8+ 6.8+ 8.4+6.6 }{7}

      \=x =  7.5571

The standard deviation is mathematically evaluated as

           \sigma  =  \sqrt{\frac{\sum  [ x -  \= x ]}{n} }

substituting values

          \sigma  =  \sqrt{\frac{  [ 9.0-7.5571]^2 + [7.3 -7.5571]^2 + [6.0-7.5571]^2 + [8.8- 7.5571]^2 + [6.8- 7.5571]^2 + [8.4 - 7.5571]^2+ [6.6- 7.5571]^2 }{7} }\sigma =  1.1774

Generally the test statistic is mathematically evaluated as

            t  =  \frac{\= x - \mu }  { \frac{\sigma }{\sqrt{n} } }

substituting values

           t  =  \frac{7.5571  - 6.6  }  { \frac{1.1774 }{\sqrt{7} } }

            t  = 1.4274

Looking at the value of  t and  Z_{\alpha }   we see that t  <  Z_{\alpha } hence we fail to reject the null hypothesis

  What this implies is that there is no sufficient evidence to state that the sample data show as significant increase in the average birth rate

The conclusion is that the mean is  \mu = 6.6  \ lb

8 0
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 <span>5x²y + 2xy² + x²y 

Combining like terms would be
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The two terms are now unique and cannot be combined any further. </span><span>
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6 0
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Answer:

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Step-by-step explanation:

Since they are parallel, they have the same slope. This will be true for any set of lines.

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4 0
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