Question 420010
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Hi
geometric sequence
{{{a[n] = a[1]*r^(n-1)}}}
{{{a[4] = a[1]*r^3 = 24}}} {{{a[1] = 24/r^3}}}
{{{a[9] = a[1]*r^8= 768}}}
          24/r^3 *r^8 = 768
                  r^5 = 32
                  r = 2  and {{{a[1] = 3}}}
{{{sum( a[n], n=1, 9 ) = a[1]((1-r^9)/(1-r))= 3(-511/-1) = 1533}}}