Sadie and Cora each want to run for president of their school's student body council. In order to do so, they must collect a certain number of signatures and get a nomination. So far, Sadie has 10 signatures, and Cora has 20. Sadie is collecting signatures at an average rate of 3 per day, whereas Cora is averaging 2 signatures every day. Assuming that their rate of collection stays the same, eventually the two will have collected the same number of signatures. How many signatures will they both have?