Question 1078548: A die is rolled 20 times and the number of twos that come up is tallied. Find the probability of getting the given result. Less than four twos
Answer by Boreal(15235)   (Show Source):
You can put this solution on YOUR website! Possibilities are 3,2,1,0 twos.
For 0, it is (5/6)^20=0.0261
For 1, is it (5/6)^19*(1/6)*20, the 20 the number of ways the two can appear.
=0.1043
For 2, it is (5/6)^18*(1/6)^2*190, the 190=20C2
=0.1982
For 3, close to the expected value of 3.33, this should be a higher probability
(5/6)^17*(1/6)^3*1140=0.2379
The sum of the 3 is 0.5402
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