The airmail rates to a country are shown.
Type | Mass | Cost |
Letters |
First 12 g | 24a¢ |
Every additional 6 g or less | 5a¢ | |
Postcards | Per piece | 70¢ |
Julian sent 3 postcards and a letter. The letter weighed 21 g. How much did Julian pay in total? Give your answer in terms of a in the simplest form.