Question

B) If you were to roll the dice 100 times, how often would you expect to get doubles?

Answer 1

If you're rolling a single cube, then ...

-- There are 6 possible out comes.

-- One of them (5) is a multiple of 5 .

-- The probability of rolling it is (1/6) = 16-2/3 % .

If everything is acting perfectly random, then ion 100 rolls,

you'd expect to succeed 16 or 17 times.

If you're rolling a pair of cubes, then ...

-- There are (6 x 6) = 36 possible outcomes.

-- There are seven ways to get a multiple of 5.

(1+4),  (4+1),  (2+3),  (3+2),  (4+6),  (6+4),  (5+5)

-- The probability of rolling one of those is

                                                            (7/36) = 19-4/9 % .

If everything is acting perfectly random, then in 100 rolls,

you'd expect to succeed 19 or 20 times.