Board Thread:Quests and Special Events/@comment-5354013-20131204195515/@comment-20699994-20131205235721

The formulas are here:  http://dragoncity.wikia.com/wiki/Viking_Island

Under the Historical Objectives Tab.

Example for Thor:

 

level = your gameplay level

Farms = the max number of farms available at your level (note that even if you have bought less farms than your maximum capability, the max capability is still used in the formula)

If you're level 40, and have 12 farms available to you:

=round(2.601*((1+40/100)^1.01)*4*12)*100

You'll either need a scientific calculator, a spreadsheet application, or using a regular calculator a few steps will be needed to calculate out the formula.