Aorganization decided to set up a lemonade stand to raise money to help fight childhood cancer. Their plan was to donate two-thirds of any money collected to the cause and keep the remainder to cover expenses. As the group was setting up, they had a young man stop by to make a flat donation of $60. If the group is selling each cup of lemonade for $0.75 and they have already collected $60, how many cups will they need to sell in order to raise at least $100 to donate to the cause?