#### Explanation:

I'm an Australian and we're more comfortable dealing with decimals. I feel like Americans are more comfortable dealing with fractions, so we could also solve this as follows:

20% is 20/100, which we can also express as 2/10 or 1/5.

If we multiply this by the bill, we get the size of the tip:

1/5 times $60.50 = ($60.50)/5 = $12.10. Adding this to the bill gives $60.50 + $12.10 =$72.60.