Answer:
a) 8.23% probability that a piece of pottery will be finished within 95 minutes
b) 0.28% probability that it will take longer than 110 minutes.
Step-by-step explanation:
Normal distribution:
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.
Two variables:
Means 
Standard deviations 
Sum:


In this question:

So


A) What is the probability that a piece of pottery will befinished within 95 minutes?
This is the pvalue of Z when X = 95.



has a pvalue of 0.0823
8.23% probability that a piece of pottery will befinished within 95 minutes.
B) What is the probability that it will take longer than 110 minutes?
This is 1 subtracted by the pvalue of Z when X = 110.



has a pvalue of 0.9972
1 - 0.9972 = 0.0028
0.28% probability that it will take longer than 110 minutes.
Answer:
Correct answer is 0.67
Step-by-step explanation:
Answer:
Slower speed = 9 mph
Step-by-step explanation:
Let the initial speed (slower speed) = s mph
Speed 's' = 
s =
-------(1)
If the cyclist increases the speed by 3 mph then the final speed = (s + 3) mph
He can reduce the time 't' by 10 minutes (
hours)
Now, (s + 3) = 
s + 3 =
--------(2)
Substitute the value of 's' from equation (1) to the equation (2).






6t² - t = 2
6t² - t - 2 = 0
6t² - 4t + 3t - 2 = 0
2t(3t - 2) + 1(3t - 2) = 0
(2t + 1)(3t - 2) = 0
t =
hours
But the time can't be negative.
Therefore, t =
hours is the answer.
From equation (1),
s = 
s = 9 miles per hour.
Slower speed = 9 mph is the answer.