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Answer:
<u><em>6</em></u> rolls because the total perimeter is 102 ft and five rolls is only 100 feet. So she needs <em><u>6</u></em> rolls.
Step-by-step explanation:
to find perimeter, add up all the side lengths.
so 15*4 (it's easier than 15+15+15...)
60 ft.
now we have to use Pythagorean's Theorum to find corner to corner.
so
we have a and b
do the math...
225+225= 450
square root of 450=
21.213
double that because it's used twice (corner to corner and corner to corner)
42.426
now add it all up
42.426 + 60 = 102.426
we can round
102
20*5 = 100
so she needs 6
MY ORIGINAL ERROR WAS 5, BUT 5 TIMES 20 IS ONLY 80, SO THEREFORE 6 IS REQUIRED SO THERE IS ENOUGH TO COVER 102.
Answer:
They should guarantee the lifetime of their batteries for 32 months.
Step-by-step explanation:
Normal Probability Distribution:
Problems of normal distributions can be solved using the z-score formula.
In a set with mean and standard deviation
, the z-score 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 p-value, we get the probability that the value of the measure is greater than X.
Mean of 36 months and a standard deviation of 2 months.
This means that
If the company wants to replace no more than 2% of all batteries, for how many months should they guarantee the lifetime of their batteries?
The guarantee should be the 2th percentile of lengths, which is X when Z has a pvalue of 0.02. So X when Z = -2.054.
Rounding to the closest month, 32.
They should guarantee the lifetime of their batteries for 32 months.