Answer:
The percentage of students who scored below 620 is 93.32%.
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean
and standard deviation
, the zscore of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this question, we have that:

Percentage of students who scored below 620:
This is the pvalue of Z when X = 620. So



has a pvalue of 0.9332
The percentage of students who scored below 620 is 93.32%.
Happy New Year from MrBillDoesMath!
Answer:
Proof by ASA congruence postulate. See below
Discussion:
Fact 1 : angle A = angle T (given)
Fact 2: The angles on both sides of point X are equal as vertical angles
are equal.
From these facts it follows that angle M = angle H (as all plane triangles have 180 degrees). Also AM = TH (given) so
In the left triangle In the right triangle
(angle M, side AM, angle A) = (angle H, side TH, angle T)
Hence the triangles have two congruent angles, and congruent sides included between the angles, so they are congruent by ASA.
Thank you,
MrB
Answer:
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Responder:
Número total de bolas = 245/23
Explicación paso a paso:
Dado que:
Bolas blancas = 1/5
Bolas negras = 1/7
Bolas rojas = 7
Sea el número total de bolas = x
Bolas blancas = 1 / 5x
Bolas negras = 1 / 7x
Por tanto, total;
(x / 5 + x / 7 + 7) = x
((7x + 5x) / 35) +7 = x
(12x / 35) + 7 = x
7 = x - 12x / 35
7 = (35x - 12x) / 35
7 = 23 veces / 35
245 = 23x
x = 245/23
9514 1404 393
Answer:
250 days
Step-by-step explanation:
If the number of drops increases by a factor of 20/8, the expected life will decrease by the inverse of that factor: 8/20.
The expected life is (8/20)(625 days) = 250 days.