Mariah Carey comes up with a new equation

On a recent Monday morning, Mariah Carey flew the red-eye from New York to Los Angeles, stopped by Ryan Seacrest’s morning radio show to chat, recorded a background vocal track for the song “I Stay in Love” for her upcoming album, then recorded a video for Wal-Mart’s “Soundcheck” series, which will be used as bonus footage online and played in stores.

By the time all of this was done, it was just past noon. Her afternoon consisted of another radio interview, and in the evening she returned to the studio to work on mastering the album, “E-MC2” — due April 15 via Island Def Jam.

If “E-MC2” scores big, Carey could find herself in elite chart company. She’s currently tied at No. 2 with Elvis Presley for the most Hot 100 No. 1 singles, with 17. The Beatles hold the crown with 20.