The probability of rolling any number of an wighted 6-sided die, with faces numbered 1 through 6, is directly proportional to the number rolled. What is the probability of getting 5, if the die is rolled only once?
A
1/6
B
5/6
C
5/16
D
5/21
Correct Answer: 5/21
If the probability of rolling a particular number is related to that number, then in 21( = 1 + 2 + 3 + 4 + 5 + 6) rollls, we'll have the following roll a '1' once, a '2' twice, a '3' thrice etc. Then th probability of those number is p(1) = 1/21 p(2) = 2/21 p(3) = 3/21 p(4) = 4/21 p(5) = 5/21 p(6) = 6/21 ∴ The probability of getting 5, if the die is rolled only once is 521