Hi Ron! I'd be happy to help you with that.

To convert decimal fractions of minutes to seconds, you need to multiply the decimal by 60. In this case, we want to convert 0.5 minutes to seconds, so we'll multiply 0.5 by 60:

1. 0.5 x 60 = 30 seconds

So 0.5 minutes is equal to 30 seconds. Now we need to add that to the original 5 minutes to get the total time in minutes and seconds.

5 minutes + 30 seconds = 5:30

However, we want the seconds to be displayed as 12 instead of 30. To do this, we need to subtract the number of seconds we want to remove (18 in this case) from the total number of seconds (30).

30 - 18 = 12

So the final answer is 5:12.

I hope that helps!