Answer:
13
Step-by-step explanation:
where n is the number of terms, a1 is the first term and an is the last term. The sum of the first n terms of an arithmetic sequence is called an arithmetic series . Example 1: Find the sum of the first 20 terms of the arithmetic series if a1=5 and a20=62 .An arithmetic sequence is a sequence where the difference between any two consecutive terms is a constant. ... As with any recursive formula, the initial term of the sequence must be given. An explicit formula for an arithmetic sequence with common difference d is given by an=a1+d(n−1) a n = a 1 + d ( n − 1 ) .
Answer:
C
Step-by-step explanation:
I don't actually know how to explain it but,
Q1=43.5
Q2=44
Q3=48.5
Sorry, I can't help more.
In this case, you first need to think about what is the formula for the circumference of a circle. <span>The formula for the circumference of a circle is 2 * PI * r, where r is the radius of the circle, and PI is the mathematical constant approximately equal to 3.14.

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So if 2 notebooks cost 12 divide that
12/2 =6 $ each
So to check if its true the 3notebooksx $6 dollars each should =$18 for 3 notebooks
5 notebooks at $6 each = $30 for 5 notebooks
so What is 4notebooks x$6 each ? =4x6 = $24 for 4 notebooks