grace and her friends were to roll the two dice 100 times, how many of the 100 times could they expect to roll the same number on each die? (In other words, the outcome would be 1,1 or 2,2 or 3,3 or 4,4.)
The probability of both dice having the same number is 636, as there are 36 different outcomes, 6 of which have two of the same number, i.e. (1,1),(2,2),....
The expected number of rolls of this type in 100 pairs of dice rolls is 100∗636
