A dietician recommends her client eat blueberries and strawberries to meet her anti-oxidant and mineral requirement. A pack of blueberries contains 3 units of anti-oxidants and 5 units of minerals. A pack of strawberries contains 1 unit of anti-oxidants and 7 units of minerals. The client must get at least 90 units of anti-oxidants and 100 units of minerals. In addition, because blueberries are not in season, the dietician recommend she eats at least 3 times as many packs of strawberries as blueberries. If a pack of blueberries contains 5 grams of sugar and a pack of strawberries contains 7 grams of sugar, how many of packs of each should she consume to minimize her sugar intake?