The airmail rates to a country are shown.
Type | Mass | Cost |
Letters |
First 16 g | 20a¢ |
Every additional 8 g or less | 7a¢ | |
Postcards | Per piece | 80¢ |
Oscar sent 4 postcards and a letter. The letter weighed 30 g. How much did Oscar pay in total? Give your answer in terms of a in the simplest form.