An unbiased coin is tossed. If the outcome is a head then a pair of unbiased dice is rolled and the sum of the numbers obtained on them is noted. If the toss of the coin results in tail then a card from a well-shuffled pack of nine cards numbered 1, 2, 3, …., 9 is randomly picked and the number on the card is noted. The probability that the noted number is either 7 or 8 is:

Options

A. `4/9`
B. `1/6`
C. `15/72`
D. `19/72`

Answer

B

Explanation

P (Noted number is 6) ` = 1/2 xx 5/36 + 1/2 xx 1/9 = 9/72`
P(Noted number is 10) ` = 1/2 xx 3/36 + 1/2 xx 0 = 3/72`
P(Noted number 6 or 10) ` = 12/72 =1/6`