The airmail rates to a country are shown.
Type | Mass | Cost |
Letters |
First 10 g | 25m¢ |
Every additional 5 g or less | 5m¢ | |
Postcards | Per piece | 90¢ |
David sent 2 postcards and a letter. The letter weighed 18 g. How much did David pay in total? Give your answer in terms of m in the simplest form.