FANDOM


12 February 2012
Item Base date Base price Price on adjustment date Comments
Coal ca. December 2007 159 320 Unchanged
Steel bar 540 1,335
Gold ore 528 304
Nature rune 271 226
Death rune 299 452
Pure essence 80 125
Yew logs 411 522
Magic logs 1,222 1,592
Cowhide 109 513
Flax 70 72
Soft clay 207 541
Limpwurt root 646 2,060
Raw lobster 237 285
Raw monkfish 10 January 2008 350 601
Snape grass 428 314
Clean snapdragon 6,885 9,866
Clean kwuarm 3,030 1,828
Law rune ca. December 2007 303 363 Removed item
Big bones 419 621
Raw swordfish 10 January 2008 325 492
Mithril ore 315 349
Vial of water 98 36
Clean ranarr 5,959 4,958
Abyssal whip 420,951 Added item
Dragon boots 103,701
Rune armour set (lg) 136,531
Red chinchompa 1,592
Oak plank 639
Shark 1,715
Green dragonhide 2,196
Dragon bones 3,962
Cannonball 407
Dragonfire shield 7,946,801

Calculations

From the old divisor obtained from the templates:

$ {div}_{\text{old}} = 21.791759207424 $


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} \\ & = \left (\frac{320}{159} + \frac{1,335}{540} + \dots + \frac{1,828}{3,030} \right ) + \left (\frac{363}{303} + \frac{621}{419} + \dots + \frac{4,958}{5,959} \right ) \\ & = 35.26980062 \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} \\ & = 35.26980062 - \left ( \frac{363}{303} + \frac{621}{419} + \dots + \frac{4,958}{5,959} \right ) + 10 \\ & = 38.76853218 \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}}} \\ & = 21.791759207424 \times \frac{38.76853218}{35.26980062} \\ & = 23.9535 \text{ (4 d.p.)} \end{align} $
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