<PRE><B>Question 720811</B>
&lt;pre&gt;
a&lt;sub&gt;2&lt;/sub&gt; - a&lt;sub&gt;1&lt;/sub&gt; = 19 - 14 = 5
a&lt;sub&gt;3&lt;/sub&gt; - a&lt;sub&gt;2&lt;/sub&gt; = 24 - 19 = 5
a&lt;sub&gt;4&lt;/sub&gt; - a&lt;sub&gt;3&lt;/sub&gt; = 29 - 24 = 5

Therefore the common difference d = 5

S&lt;sub&gt;n&lt;/sub&gt; = {{{n/2}}}[2a&lt;sub&gt;1&lt;/sub&gt; + (n-1)d]

S&lt;sub&gt;60&lt;/sub&gt; = {{{60/2}}}[2(14) + (60-1)5]

S&lt;sub&gt;60&lt;/sub&gt; = 30[28 + (59)5]

S&lt;sub&gt;60&lt;/sub&gt; = 30[28 + 295]

S&lt;sub&gt;60&lt;/sub&gt; = 30[323]

S&lt;sub&gt;60&lt;/sub&gt; = 9690

Edwin&lt;/pre&gt;</PRE>