Question 760241
DEFINITIONS: {{{b[1]}}} = first term, and {{{r}}} = common ratio
FORMULAS: {{{b[n]=r*b[n-1]}}} and {{{b[n]=b[1]*r^(n-1)}}}
 
So {{{b[3]=b[1]*r^2}}}, and {{{b[6]=b[1]*r^5}}}.
Then {{{b[6]/b[3]=b[1]*r^5/b[1]/r^2}}} --> {{{b[6]/b[3]=r^5/r^2}}} --> {{{b[6]/b[3]=r^3}}}
{{{b[6]/b[3]=1215/360=135*9/40/9=135/40=27/8=3^3/2^3=(3/2)^3}}}
{{{system(b[6]/b[3]=r^3,b[6]/b[3]=(3/2)^3)}}} --> {{{highlight(r=3/2)}}}
 
{{{system(b[3]=360,b[3]=b[1]*r^2,r=3/2)}}} --> {{{360=b[1]*(3/2)^2}}} --> {{{360=b[1]*(9/4)}}} --> {{{b[1]=360*(4/9)}}} --> {{{highlight(b[1]=160)}}}