ANSWER

EXPLANATION
We want to find the number of years that it will take the population to double.
To do this, we have to apply the exponential growth function:

where y = final value
a = initial value
r = rate of growth
t = time (in years)
For the population to double, it means that the final value must be 2 times the initial value:

Substitute the given values into the function above:

To solve further, convert the function from an exponential function to a logarithmic function as follows:

Solve for t:

It will take 9 years for the population to double.
See the attachment below gor graph
hope that helps
X best represents
the width must be x so that the length can be 12+x meaning that the length is greater than length by 12
Answer:
The percentle for Abby's score was the 89.62nd percentile.
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean
and standard deviation(which is the square root of the variance)
, 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.
Abby's mom score:
93rd percentile in the math SAT exam. In 1982 the mean score was 503 and the variance of the scores was 9604.
93rd percentile. X when Z has a pvalue of 0.93. So X when Z = 1.476.

So




Abby's score
She scored 648.

So



has a pvalue of 0.8962.
The percentle for Abby's score was the 89.62nd percentile.