Evaluate the expression. Drag the answer into the box to match the expression.
2 answers:
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Answer:
The rocket hits the ground at a time of 11.59 seconds.
Step-by-step explanation:
The height of the rocket, after x seconds, is given by the following equation:
It hits the ground when , so we have to find x for which
, which is a quadratic equation.
Finding the roots of a quadratic equation:
Given a second order polynomial expressed by the following equation:
.
This polynomial has roots such that
, given by the following formulas:
In this question:
So
Since time is a positive measure, the rocket hits the ground at a time of 11.59 seconds.
Answer:
6.18% of the class has an exam score of A- or higher.
Step-by-step explanation:
When the distribution is normal, we use 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:
What percentage of the class has an exam score of A- or higher (defined as at least 90)?
This is 1 subtracted by the pvalue of Z when X = 90. So
has a pvalue of 0.9382
1 - 0.9382 = 0.0618
6.18% of the class has an exam score of A- or higher.