tolong jawab dengan cara

udah belajar notasi sigma? kalo udah semoga paham
[tex]\sum_{i=1}^{n} (2n-1)=2\sum_{i=1}^{n} n - \sum_{i=1}^n 1 = 2\frac{n(n+1)}{2} - n=n(n+1)-n=n^{2}-n+n=n^{2}[/tex]
[tex]\sum_{i=1}^{n} 2n = 2\sum_{i=1}^{n} n = 2\frac{n(n+1)}{2}=n(n+1)[/tex]

[tex]\frac{1+3+5+...+(2n-1)}{2+4+6+...+2n}=\frac{\sum_{i=1}^{n} (2n-1)}{\sum_{i=1}^{n} 2n}=\frac{n^{2}}{n(n+1)}=\frac{n}{n+1}[/tex]

[tex]\frac{n}{n+1}=\frac{115}{116}[/tex]
[tex]n=115[/tex]