lemon made 8 5/8 cups of lemonade. she drank 4 3/8 cups of the lemonade. how many cups of lemonade does she have left

For the rule of 78, for a 12-month period, the last term in the sequence is 12 and the series sums to 78. for an 10 month period, the last term is and the series sum is . for a 15 month period, the last term is and the series sum is . for a 20 month period, the last term is and the series sum is