The airmail rates to a country are shown.
Type | Mass | Cost |
Letters |
First 16 g | 28r¢ |
Every additional 8 g or less | 10r¢ | |
Postcards | Per piece | 90¢ |
Sean sent 4 postcards and a letter. The letter weighed 39 g. How much did Sean pay in total? Give your answer in terms of r in the simplest form.