Question 750669

the sum of 4+17/4+9/2+... 

nth term formula is:

{{{sum(n/4+15/4,n=1,infinity)}}}

to be greater then {{{80}}}, find {{{n}}} for what {{{n/4+15/4>80}}}

 {{{(n+15)/4>80}}}

{{{n+15>80*4}}}

{{{n+15>320}}}

{{{n>320-15}}}

{{{n>305}}}

check: if {{{n=306}}}

 {{{(306+15)/4>80}}}

 {{{321/4>80}}}

{{{80.25>80}}}