Answer:
Step-by-step explanation:
Required
15 is what percentage of 105
To do this, simply divide 15 by 105 multiplied by 100%.
So, we have:
--- approximated
A metalworker has a metal alloy that is 20% copper and another alloy that is 60% copper. How many kilograms of each alloy shou
ld the metalworker combine to create 100 kg of a 52% copper alloy?
The metalworker should use
_______ of the metal alloy that is 20% copper and ___ kilograms
of the metal alloy that is 60% copper
(Type whole numbers.)
The metalworker should use
_______ of the metal alloy that is 20% copper and ___ kilograms
of the metal alloy that is 60% copper
(Type whole numbers.)
1 answer:
<h3>Answer:</h3>
- <u>20</u> kg of 20%
- <u>80</u> kg of 60%
I like to use a little X diagram to work mixture problems like this. The constituent concentrations are on the left; the desired mix is in the middle, and the right legs of the X show the differences along the diagonal. These are the ratio numbers for the constituents. Reducing the ratio 32:8 gives 4:1, which totals 5 "ratio units". We need a total of 100 kg of alloy, so each "ratio unit" stands for 100 kg/5 = 20 kg of constituent.
That is, we need 80 kg of 60% alloy and 20 kg of 20% alloy for the product.
_____
<em>Using an equation</em>
If you want to write an equation for the amount of contributing alloy, it works best to let a variable represent the quantity of the highest-concentration contributor, the 60% alloy. Using x for the quantity of that (in kg), the amount of copper in the final alloy is ...
... 0.60x + 0.20(100 -x) = 0.52·100
... 0.40x = 32 . . . . . . . . . . .collect terms, subtract 20
... x = 32/0.40 = 80 . . . . . kg of 60% alloy
... (100 -80) = 20 . . . . . . . .kg of 20% alloy
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Using the normal distribution, it is found that:
a)
b) There is a 0.5859 = 58.59% probability that the college graduate has between $14,200 and $33,950 in student loan debt.
c) Low: $23,519.65, High: $26,580.35.
<h3>Normal Probability Distribution</h3>The z-score of a measure X of a normally distributed variable with mean and standard deviation
is given by:
- The z-score measures how many standard deviations the measure is above or below the mean.
- Looking at the z-score table, the p-value associated with this z-score is found, which is the percentile of X.
The mean and the standard deviation are given, respectively, by:
.
Hence the distribution of X can be described as follows:
The probability that the college graduate has between $14,200 and $33,950 in student loan debt is the <u>p-value of Z when X = 33950 subtracted by the p-value of Z when X = 14200</u>, hence:
X = 33950:
Z = 0.73
Z = 0.73 has a p-value of 0.7673.
X = 14200:
Z = -0.91
Z = -0.91 has a p-value of 0.1814.
0.7673 - 0.1814 = 0.5859.
There is a 0.5859 = 58.59% probability that the college graduate has between $14,200 and $33,950 in student loan debt.
Considering the symmetry of the normal distribution, the middle 10% is between the 45th percentile(X when Z = -0.127) and the 55th percentile(X when Z = 0.127), hence:
X - 25150 = -0.127(12050)
X = $23,519.65.
X - 25150 = 0.127(12050)
X = $26,580.35.
More can be learned about the normal distribution at brainly.com/question/4079902
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