Here's the problem (fairly simple but I'm still getting it wrong with the book's result...):
A yearly output of a silver mine is found to be decreasing by 25% of it's previous year's output. If in a certain year it's output was 25,000,000£ what could be reckoned as it's total future output...
the book gives me 3.3 x 10 to the power 7.
Is that right?