singhsa Master | Next Rank: 500 Posts View User Profile Posts: 107 Joined: Sat Feb 27, 2010 11:10 am GMAT Score:690 reduction of vs by by singhsa » Tue Sep 14, 2010 2:01 pm Hi, In case we are confronted with a sentence in the GMAT in which, either "X caused a reduction of 20%" or "X caused a reduction by 20%" is used, which one of the 2 should we pick? Experts....plzzz Top Quote