Hello requalThe compound interest formula gives the amount A after n years as:

So into this formula you have to plug in each of the values of and , equate the two and solve for to find the point at which the two amounts become equal.

Now - and here's the key step - take logs of both sides (it doesn't matter which base of logs you use):

So by the end of year 11, the first investment will be worth more than the second.

Grandad