Question 255435
In the sequence 3,8,13,18, what term of the series is the number 2218?
<pre><font size = 4 color = "indigo"><b>
This is a sequence (not "series" unless they are
added together, with + signs between).

Note that the 2nd term - 1st term = 8-3 = 5

Note that the 3rd term - 2nd term = 13-8 = 5

Note that the 4th term - erd term = 18-13 = 5

That tells us that this is an arithmetic sequence 
with common difference, d=5.

The formula for the nth term {{{a[n]}}} of an arithmetic
sequence is

{{{a[n]=a[1]+(n-1)*d}}}

{{{2218=3 + (n-1)*5}}}

{{{2215=5(n-1)}}}

Divide both side by 5

{{{443=n-1}}}

{{{444=n}}}

So {{{a[444]=2218}}}, the 444th term.

Edwin</pre>