<PRE><B>Question 1193591</B>
&lt;br&gt;
You have received two responses that show two very different ways of solving the problem, both of which are valid.&lt;br&gt;
Here is a third (still very different) method....&lt;br&gt;
The sequence is clearly neither geometric nor arithmetic.  But we can make it into an arithmetic sequence by pairing the terms:&lt;br&gt;
1+2=3
4+5=9
7+8=15
.
.
.
97+98=195&lt;br&gt;
So the sum is&lt;br&gt;
3+9+15+...+195&lt;br&gt;
That is an arithmetic sequence with first term 3, last term 195, and common difference 6.  The sum of the sequence is&lt;br&gt;
(number of terms) times (average of all the terms)&lt;br&gt;
Since the sequence is arithmetic, the average of all the terms is the average of the first and last: (3+195)/2=99&lt;br&gt;
The number of terms is&lt;br&gt;
(last term minus first term), divided by 6, plus 1&lt;br&gt;
The difference between the first and last terms, divided by the common difference, tells you the number of terms AFTER THE FIRST ONE; that&#39;s why you need to add 1 at the end.&lt;br&gt;
195-3=192; 192/6=32; 32+1=33&lt;br&gt;
So we have a sequence of 33 terms with an average of 99; the sum is&lt;br&gt;
33(99)=33(100-1) = 3300-33 = 3267&lt;br&gt;
ANSWER: 3267&lt;br&gt;
</PRE>