Answer:
a.

b.

Explanation:
We are given that a die is rolled
Let x bet the cases in favor of 5.
Number of cases in favor of 6=x
Then according to question
Number of cases in favor of 1=3x
Number of cases in favor of 2=3x
Number of cases in favor of 3=3x
Number of cases in favor of 4=3x
Sum of total cases=

Probability of getting 5 =
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Probability of getting 1=

1.We have to find probability should be assigned to rolling a 4.
The probability of getting =

2.We have to find the probability of rolling 6.
The probability of getting 6=
