If an amount of $100 in a savings account increases by 10%, then increases by 10% again, is that the same as increasing by 20%?
No, and this can be shown as follows:
10% of $100 is $10. We then add this together to give $110.
Now, another 10% increase, this time on $110 gives an $11 increase.
Adding this together gives a final total of $121.
20% of $100 is $20. We then add this together to give $120.