question: 20% of 50 people think horse #2 will win the big race.  60% of the remaining people think horse #7 will win.  The rest of the people think horse #12 will win the big race.  How many people think that horse #12 will win?
answer: 20% of 50 people are pulling for horse #2 so that's .20*50 = <<.20*50=10>>10 people
  10 out of 50 people think horse #2 will win which leaves 50-10 = <<50-10=40>>40 people
  60% of 40 people think horse #7 will win so that's .60*40 = <<60*.01*40=24>>24 people
  That leaves 40-24 = <<40-24=16>>16 people that think horse #12 will win
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