The table shows the results of rolling a number cube, with sides labeled 1 through 6, several times.
what is the experimental probability of rolling a 1 or a 5?
express your answer in simplest form.
outcome 1 2 3 4 5 6
number of times outcome occurred 10 6 4 8 6 6

Total number of rolls in the experiment:  (10 + 6 + 4 + 8 + 6 + 6)  = 40 .

Number of times  '1'  or  '5'  came up:  (10 + 6) = 16 .

Experimental probability of  '1'  or  '5'  :   16/40  =  40%
(Could change, and most likely will, in the next experiment.) 

Theoretical probability:  2/6  =  33-1/3 %