Answer:
67.75%
Step-by-step explanation:
Given:
Given that:
µ = 76 ; σ = 4.7
P(x < 80.7) - P(x < 71.4)
Obtain the standardized score, Z ; x = 71. 4
Zscore = (x - μ) / σ
P(x < 71.4) = (71.4 - 76) / 4.7
P(x < 71.4) = - 4.6 / 4.7
P(x < 71.4) = - 0.9787
P(z < 0.9787) = 0.16386
x = 80.7
P(x < 80.7) = (80.7 - 76) / 4.7
P(x < 80.7) = 4.7 / 4.7
P(x < 80.7) = 1
P(z < 1) = 0.84134
0.84134 - 0.16386 = 0.67748 = 67.748% = 67.75%
<span>valid. She used a representative sample
</span>because she correctly found the average and 18,000 is a reasonable number to get for a the problem
X = number of dimes
y = number of quarters
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10x + 25y = 2565
y = x + 20
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put the system of linear equations into standard form
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10x + 25y = 2565
x - y = -20
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copy and paste the above standard form linear equations in to this solver:
https://sooeet.com/math/system-of-linear-equations-solver.php
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solution:
x = 59
y = 79
As far as I can tell, that isn't a function at all.
x = 0 produces y = -2 and y = 4, which can't happen.
Please don't use all caps, that's really, really irritating.
