Question: A lemonade stand sold only small and large cups of lemonade on Tuesday. 3/5 of the cups sold were small and the rest were large. If the large cups were sold for 7/6 as much as the small cups, what fraction of Tuesday's total revenue was from the sale of large cups?
Explanation: Since the large cups were sold at 7/6 as much per cup as the small cups.
Comment: It is nowhere written that EACH large cup sold at 7/6 of the EACH small cup.
The question statement rather suggests that Total revenue from large cups was 7/6 of the total revenue from small cups.