Albert and Molly design posters. In December, they each worked for 25 days and made 20 posters. Molly was on vacation in the beg
inning of January, so Albert worked for 10 days before Molly could join him. Together, they worked another 15 days and made a total of 15 posters. How many posters can Molly make if she works alone for 10 days?
