Simplify (5.8x-3d+d)-(7x-2.5d)
1 answer:
You might be interested in
Answer:
1) 68%
2) 68%
Step-by-step explanation:
<h2>1) The ages of trees</h2>We know the mean and the standard deviation.
The mean is:
The standard deviation is:
The Z-score formula is:
For x=20 the Z-score is:
For x=30 the Z-score is:
Then we look for the percentage of the data that is between deviations from the mean.
According to the empirical rule 68% of the data is less than 1 standard deviations of the mean. This means that 68% of the trees are between 20 and 30 years old
<h2>2) Pizza delivery </h2>First we calculate the Z-scores
We know the mean and the standard deviation.
The mean is:
The standard deviation is:
The z-score formula is:
For x=24 the Z-score is:
For x=30 the Z-score is:
Then we look for the percentage of the data that is between deviations from the mean.
According to the empirical rule 68% of the data is less than 1 standard deviations of the mean. This means that 68% of pizzas are delivered between 24 and 30 minutes