Question

If pair of dice are rolled, what is the probability of getting (i) A total of 9. (ii)

Same faces on both dices.

Answer 1

I) 1/9; II) 1/6.

Explanation:

I) a total of 9 is possible, if: 4+5; 5+4; 3+6; 6+3.

The probability of 4+5 is 1/6*1/6; of 5+4 is 1/6*1/6, of 3+6 is 1/6*1/6; of 6+3 is 1/6*1/6.

The required probability is:

1/6*1/6+1/6*1/6+1/6*1/6+1/6*1/6=1/36 *4=1/9.

II) the same faces on both dices is possible, if: 1+1; 2+2; 3+3; 4+4; 5+5; 6+6.

The probability of 1+1 is 1/6*1/6; of 2+2 is 1/6*1/6; 3+3 is 1/6*1/6; 4+4 is 1/6*1/6; 5+5 is 1/6*1/6; 6+6 is 1/6*1/6.

The required probability is:

1/6*1/6+1/6*1/6+1/6*1/6+1/6*1/6+1/6*1/6+1/6*1/6=6* 1/36=1/6