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Mkey [24]
3 years ago
9

A chemist begins studying a radioactive sample that has a mass of 450 grams.

Mathematics
1 answer:
77julia77 [94]3 years ago
5 0

Answer:

The question should say..... How much of the sample is left in......FIVE.....weeks? At least that is what I think you want to know.

The answer is 318.13 grams.

Step-by-step explanation:

450 - 6.7% = 419.85 grams ---- End of week 1

419.85 - 6.7% = 391.72 grams ---- End of week 2

391.72 - 6.7% = 365.47 grams ---- End of week 3

365.47 - 6.7% = 340.98 grams ---- End of week 4

340.98 - 6.7% = 318.13 grams ------ End of week 5

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makvit [3.9K]
B) 0.019

0.019 = 1.9%
6 0
3 years ago
A recipe for chili uses 1 1/2 times the recipe which equation helps Keith find how many cups of beans he needs
rewona [7]

Answer

multiplication

Step-by-step explanation:

8 0
3 years ago
Keisha solved the following equation: 4x − 2x + 8 = 6(x + 4) Step Work Justification 1 2x + 8 = 6(x + 4) Combine like terms 2 2x
kolbaska11 [484]

4x - 2x + 8 = 6(x + 4)   Given

(4x - 2x) + 8 = 6(x + 4)

2x + 8 = 6(x + 4)     Combine like terms

2x + 8 = (6)(x) + (6)(4)

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2x - 6x + 8 = 6x - 6x + 24

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-4x + 8 - 8 = 24 - 8

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4 0
3 years ago
Assume that different groups of couples use the XSORT method of gender selection and each couple gives birth to one baby. The XS
olganol [36]

Answer:

Mean and Standard deviation for the numbers of girls in groups of 36 births are 18 and 3 respectively.

Step-by-step explanation:

We are given that he X SORT method is designed to increase the likelihood that a baby will be a girl, but assume that the method has no effect, so the probability of a girl is 0.5.

Now consider a group consisting of 36 couples.

The above situation can be represented through binomial distribution;

P(X=r)=\binom{n}{r} \times p^{r} \times (1-p)^{n-r} ;x=0,1,2,3,.....

where, n = number of trials (samples) taken = 36 couples

            r = number of success

            p = probability of success which in our question is probability

                   of a girl, i.e.; p = 0.5

<em><u>Let X = Numbers of girls in groups of 36 births </u></em>

So, X ~ Binom(n = 36, p = 0.5)

Now, mean for the numbers of girls in groups of 36 births is given by;

         <u>Mean</u>, E(X) = n \times p = 36 \times 0.5 = 18

Also, standard deviation for the numbers of girls in groups of 36 births is given by;

        <u>Standard deviation</u>, S.D.(X) =  \sqrt{n\times p\times (1-p)}

                                                      =  \sqrt{36\times 0.5\times (1-0.5)}

                                                      =  3

3 0
3 years ago
If 1/2 is the fraction representing the ratio of corresponding sides of two similar
Lynna [10]

Answer:

1/4

Step-by-step explanation:

The ratio of the areas is the square of the ratio of the lengths of sides.

(1/2)² = 1/4

Answer: 1/4

7 0
2 years ago
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