DJ Ella is making a playlist for an mp3 player; she is trying to decide what 9 9 songs to play and in what order they should be played. If she has her choices narrowed down to 21 21 hip-hop, 18 18 pop, and 15 15 disco songs, and she wants to play an equal number of hip-hop, pop, and disco songs, how many different playlists are possible? Express your answer in scientific notation rounding to the hundredths place.

The swimming pool is open when the high temperature is higher than 20∘c. lainey tried to swim on monday and thursday (which was 33 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 33 days. write an inequality to determine the rate of temperature decrease in degrees celsius per day, d, from monday to thursday.