SOLUTION: how many terms are needed to make the sum of 4+17/4+9/2+... first exceed 80?

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Question 750669: how many terms are needed to make the sum of 4+17/4+9/2+... first exceed 80?
Answer by MathLover1(20850) About Me  (Show Source):
You can put this solution on YOUR website!

the sum of 4+17/4+9/2+...
nth term formula is:
sum%28n%2F4%2B15%2F4%2Cn=1%2Cinfinity%29
to be greater then 80, find n for what n%2F4%2B15%2F4%3E80
%28n%2B15%29%2F4%3E80
n%2B15%3E80%2A4
n%2B15%3E320
n%3E320-15
n%3E305
check: if n=306
%28306%2B15%29%2F4%3E80
321%2F4%3E80
80.25%3E80