Donald will have 20x+10 dollars
The arithmetic mean provides a single measure for a certain population, also called the average.
The sum of a set of numbers divided by the total number of numbers in the set is known as the arithmetic mean or arithmetic average in mathematics and statistics.
The ratio of the total number of observations divided by the sum of all the given observations is known as the arithmetic mean. For instance, if the data set contains 5 observations, it is possible to get the arithmetic mean by adding all 5 of the given observations and dividing by 5.
Learn more about arithmetic mean here
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Luckily for us, this problem solved the bulk of its own question!
Now, all we have to do is solve for "x", or the amount of fiction books and plug its value back into the original equation to find the value of "y", or the amount of nonfiction books.
2x = 38
x = 19
There are 19 fiction books.
x + y = 26
19 + y = 26
y = 7
There are 7 nonfiction books.
Hope this helps!
Answer:
the perimeter of the square is 9 and the area would be 90