I need help. 2/7 of _ is 14?
1 answer:
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Answer:
a) 2.84% probability that he is late for his first lecture.
b) 5.112 days
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:
a. Find the probability that he is late for his first lecture.
This is the probability that he takes more than 20 minutes to walk, which is 1 subtracted by the pvalue of Z when X = 20. So
has a pvalue of 0.9716
1 - 0.9716 = 0.0284
2.84% probability that he is late for his first lecture.
b. Find the number of days per year he is likely to be late for his first lecture.
Each day, 2.84% probability that he is late for his first lecture.
Out of 180
0.0284*180 = 5.112 days
Two options are given to Tina. We find how much she pays for each option, and the one in which she pays less offers the better value.
Tina sends 12 text messages each day in June
June has 30 days, so in June, Tina sent 12*30 = 360 text messages.
Package A:
First 100 messages cost 3p, the next 100 cost $2 and after that each costs $1.
She sends 360 messages, with:
The first 100 costing 3p.
The next 100 costing 2p.
The final 360 - 200 = 160 costing 1p.
She pays:
Package B:
2p for each message, 360 messages, so:
360*2p = 720p.
Which package is better?
Package A costs less, thus, it offers her the better value for money in 30 days.
Another example of a problem in which a person has to choose between two packages is given in brainly.com/question/10693932