DJ Davon is making a playlist for an internet radio show; he is trying to decide what 1212 songs to play and in what order they should be played. If he has his choices narrowed down to 1515 rock, 2020 blues, and 1515 disco songs, and he wants to play an equal number of rock, blues, and disco songs, how many different playlists are possible? Express your answer in scientific notation rounding to the hundredths place.

Which type of tab stop is most for weights and measurements?

Suppose there is a relation r(a, b, c) with a b+-tree index with search keys (a, b).1. what is the worst-case cost of finding records satisfying 10 < a < 50 using this index, in terms of the number of records n1, retrieved and the height h of the tree? 2. what is the worst-case cost of finding records satisfying 10 < a < 50 and 5 < b < 10 using this index, in terms of the number of records n2 that satisfy this selection, as well as n1 and h defined above? 3. under what conditions on n1 and n2, would the index be an efficient way of finding records satisfying the condition from part (2)?

Plz ( which is an example of a good url?