Answer:
9.18% probability the miners find more than 16 ounces of gold in the next 1000 tons of dirt excavated
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 is the probability the miners find more than 16 ounces of gold in the next 1000 tons of dirt excavated?
This is 1 subtracted by the pvalue of Z when X = 16. So



has a pvalue of 0.9082
1 - 0.9082 = 0.0918
9.18% probability the miners find more than 16 ounces of gold in the next 1000 tons of dirt excavated
3/4 and 3/8 have to have equal denominators, so multiply 3/4 by 2/2 because it's equal to one, so it doesn't change the value of the fraction, but it makes the denominator (the number on the bottom) bigger.
3/4 x 2/2 = 6/8
Now subtract.
6/8 - 3/8 = 3/8
Don't subtract the denominators.
3/8 can't be simplified.
Since your scale is 1ft:1.26cm, a 30-ft tall school would need to have a

cm model. Dividing this by how tall each toothpick is, you'll get:
ANSWER: The model would be 6 toothpicks tall.
To find out how many cotton swabs you'll need, we just divide 37.8 by how tall each swab is:
ANSWER: The model would be 5 cotton swabs tall.