Andy has 9 math books and 6 reading books. if he wants to distribute them evenly among some bookshelfs so that each has the same combanation of books, with none leftover, what is the greatest number of bookshelfs andy can use

The swimming pool is open when the high temperature is higher than 20∘c. lainey tried to swim on monday and thursday (which was 3 days later). the pool was open on monday, but it was closed on thursday. the high temperature was 30∘c on monday, but decreased at a constant rate in the next 3 days. write an inequality to determine the rate of temperature decrease in degrees celsius per day, d, from monday to thursday.