Answer:
17.3 cigarettes represent the 35th percentile
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 problem, we have that:

What number of cigarettes would represent the 35th percentile?
This is the value of X when Z has a pvalue of 0.35. So it is X when Z = -0.385.
So




17.3 cigarettes represent the 35th percentile
In scientific form or standard form?
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The value of e can be found by using pythagorean theorem, so it is
e² = d² + f², so e = sqrt (<span>d² + f²)</span>
Change the ratios to decimals and compare:
7 / 12 = 0.583
7 / 8 = 0.875
So 7:12 is less than 7/8
The answer is <