A six- sided number cube is to be rolled 30 times. How many times do you expect to roll an even number?
Since there are 3 even numbers on a six- sided number cube (2, 4, 6) and a total of 6 sides, the probability of rolling an even number on a single roll is 3/6 or 0.5.
To find the expected number of times of rolling an even number in 30 rolls, you multiply the probability of rolling an even number on a single roll by the total number of rolls:
0.5 x 30 = 15
Therefore, you would expect to roll an even number 15 times out of 30 rolls.