Step-by-step explanation:
volume of the cyclinder=πr²h
=π×6²×12
=432π cm³
volume of a cone=1/3πr²h
=1/3π×9×8
=24π cm³
number of cones=432π/24π=18 cones
Using the normal distribution, it is found that there is a 0.877 = 87.7% probability of a bulb lasting for at most 569 hours.
<h3>Normal Probability Distribution</h3>
The z-score of a measure X of a normally distributed variable with mean
and standard deviation
is given by:

- The z-score measures how many standard deviations the measure is above or below the mean.
- Looking at the z-score table, the p-value associated with this z-score is found, which is the percentile of X.
The mean and the standard deviation are given, respectively, by:

The probability of a bulb lasting for at most 569 hours is the <u>p-value of Z when X = 569</u>, hence:


Z = 1.16
Z = 1.16 has a p-value of 0.877.
0.877 = 87.7% probability of a bulb lasting for at most 569 hours.
More can be learned about the normal distribution at brainly.com/question/24663213
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We find the length of the arc followed by the needle. For this, we first need to convert the subtended angle to radians:
96/∅ = 180/π
∅ = 1.68 rad
S = r∅
S = 24 x 1.68
Distance covered by needle = 40.32 cm
Find the total points for each group:
31 students averaged 82, so the total points were 31 x 82 = 2542
2 students averaged 88, so the total points were 2 x 88 = 176
Now add the total points and divide by 33 students (31 +2):
2542 + 176 = 2718
2718 / 33 = 82.36
The average is 82.36 ( Round as needed).
6$ for 13 but I can’t see instructions