A singer has 50 microphones that he wants to arrange in pairs on a stage. While making the arrangement, he realizes that 20% of the microphones won't find any space to fit in after arranging the rest in pairs. How many pairs of microphones was he able to arrange on the stage?
The number of microphones that were not able to find space on the stage is 20/100*50 = <<20/100*50=10>>10
This means the singer could set 50-10 = <<50-10=40>>40 microphones into pairs on the stage.
Since a pair has 2 microphones, the singer set up 40/2 = <<40/2=20>>20 pairs of microphones on the stage.
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