Martha is hoping that her parents will agree to a family visit to Rockworld Zoo as a treat for her 16th birthday. This would include Martha, her mum and dad, her brothers aged 14, 12 and 9 years old and her grandmother, who is 62. They have looked at the price tariff for tickets and have decided that they would want to book online the day before the proposed visit and that they could go either on Martha's birthday or on the day before it. The table shows the possible ticket prices.