Carmen's Cafe offers two kinds of espresso: single-shot and double-shot. Yesterday afternoon, the cafe sold 80 espressos in all, 24 of which were single-shot. What percentage of the espressos were single-shot?

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