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| Question 866146:  A history teacher gives a 20-question true-false exam. In how many ways can the test be answered if the possible answers are T or F or possibly to leave the answer blank?
 Answer by jim_thompson5910(35256)
      (Show Source): 
You can put this solution on YOUR website! There are 3 possible responses (T, F, B ... B for blank). 
 
 There are 20 slots.
 
 
 So we will have
 
 
           3*3*3*3  *  3*3*3*3   *   3*3*3*3   *   3*3*3*3   *   3*3*3*3 = 3^20 = 3,486,784,401 different ways to answer this test.
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