1/5+1/4+2/5 this is adding fractions with unlike denominators what is the answer

What you would do is change all the fractions to 20ths so they have a common denominator. For 1/5, you multiply 4x5 to get 20 in the denominator. Whatever you multiply on the bottom, you must do at the top. Do that for all fractions and you would get this:
4/20 + 5/20 + 8/20= 17/20 because denominator stays the same, add the values in the numerator.
ANSWER: 17/20

ProbabilityThe extent to which an event is likely to occur, measured by the ratio of the favorable cases to the whole number of cases possible.Theoretical ProbabilityWhat is EXPECTED to happen based on the possible outcomes, assuming equally likely events.Experimental ProbabilityThe RESULT of an experiment or simulation after a large number of trials.