RuneScape:Grand Exchange Market Watch/Adjustments (14 October 2011)

14 October 2011

Adjusted index: Rune Index Adjustment date: 14 October 2011 Affected templates: Template:GE Rune Index and Template:GE Rune Index/Diff Added item(s): Armadyl rune Removed item(s): None Items before adjustment: 14 Items after adjustment: 15 Divisor before adjustment: 14.000 Divisor after adjustment:15.5671 Item Base date Base price Price on adjustment date Comments Air rune 15 December 2007 11 6 Unchanged Mind rune 10 3 Water rune 15 6 Earth rune 11 13 Fire rune 10 4 Body rune 9 5 Cosmic rune 140 107 Chaos rune 102 38 Nature rune 258 100 Law rune 304 158 Death rune 299 181 Astral rune 132 81 Blood rune 336 211 Soul rune 335 556 Armadyl rune – – 1,817 Added item Calculations From the old divisor obtained from the templates: ${div}_{\text{old}} = 14.0000$ We need to calculate a new divisor: ${div}_{\text{new}} = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}}$ To calculate the new divisor, we need to find: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{old}} & = \text{sum of ratios prior to change} \\ & = \frac{6}{11} + \frac{3}{10} + \frac{6}{15} + \dots + \frac{556}{335} \\ & = 8.93366198 \text{ (up to 8 d.p.)} \end{align}$ And also: $\begin{align} \sum \left ( \frac{p}{q} \right )_{\text{new}} & = \text{sum of ratios prior to change} - \text{sum of removed ratios} + \text{sum of added ratios} \\ & = \sum \left ( \frac{p}{q} \right )_{\text{old}} - \text{sum of removed ratios} + \text{number of added items} \\ & = 8.93366198 - 0 + 1 \\ & = 9.933661982 \text{ (up to 8 d.p.)} \end{align}$ Thus, the new divisor is: $\begin{align} {div}_{\text{new}} & = {div}_{\text{old}} \times \frac{\sum \left ( \frac{p}{q} \right )_{\text{new}}}{\sum \left ( \frac{p}{q} \right )_{\text{old}}} \\ & = 14.0000 \times \frac{9.93366198}{8.93366198} \\ & = 15.5671 \text{ (4 d.p.)} \end{align}$