Question

A six-sided number cube numbered 1 through 6 is rolled 2 times.What is the probability of getting an even number on both rolls?

Answer 1

The question is not entirely clear. If you are asking “what is the probability of rolling a 6 on the first roll and then rolling a 4 on the second roll?,” the probability of rolling a 6 on the first roll is 1/6, the probability of rolling a 4 on the second roll is also 1/6, and the probability of getting first a 6 and then a 4 in two consecutive rolls is 1/36.

But you didn’t specify that the rolls had to be consecutive. If you roll a large enough number of times, the probability of getting a 6 at some point, followed (some unspecified number of rolls later) by a 4 is virtually 100%.

Answer 2

1/4 OR 0.25

Explanation:

The probability for rolling any even number on that six sided cube is 1/2. (2, 4, 6).

Therefore,

(Probabilty of choosing an even number) • (Probabilty of choosing an even number) = (Probabilty of choosing an even number twice)

1/2 • 1/2 = 1/4

This can also be proven by doing a probability table wich takes 10 times longer than this quick equation. Any problems you have that follow this wording should be solved by using an equation like the one above.

NOTE: If the problem stated “what is the probability of getting an even number the first roll and a different even number on the second roll?” this would be solved as so:

1/2 • 1/3 = 1/6

This is because after one even number is chosen, the probabilty of choosing an even number drops by 1/6, which causes the probability for choosing any even number to change to 1/3.