From Boxofficemojo.com:

Iron Man 2 opened with an estimated $133.6 million this weekend, and "accounted for nearly three quarters of overall business, while last weekend's top grosser, A Nightmare on Elm Street (2010), predictably fell into the abyss as horror movies often do. The slasher remake bled 72 percent to an estimated $9.2 million, bringing its total to $48.5 million in ten days. Its drop was steeper than Freddy Vs. Jason and Halloween (2007) (each was off 64 percent), but smaller than Friday the 13th (2009), which had an 80 percent crash."

A Nightmare on Elm Street Week Two: -72.1% change ($9,170,000)
Total Gross - $48,530,000