Question

two dice are rolled 120 times. how many times would you expect an even number to appear on both dice? ? times

Explanation:

Step1: Find probability of even on one die

On a die, there are 3 even numbers out of 6. So probability of even on one die is $\frac{3}{6}=\frac{1}{2}$.

Step2: Find probability of even on both dice

Since the rolls are independent, probability of even on both dice is $\frac{1}{2}\times\frac{1}{2}=\frac{1}{4}$.

Step3: Find expected number of times

Multiply total rolls by probability: $120\times\frac{1}{4} = 30$.

Answer:

30