Question

find the probability of getting a sum of 7 or 8 in throwing a die twice

Answer 1

0 is the answer yar.....

Answer 2

Probability of getting sum of 7 or 8 is $\bold{\frac{11}{36}}$ when the dice is thrown twice.

Solution:

The total possibility of numbers when throwing 2 dices is used as Sample Space for the problem:  

$36 = 6 \times 6$

Possible combination of 2 dices casted is {1,2,3,4,5,6} and {1,2,3,4,5,6}

Possibility for sum 7 on the 2 dies casted  = 6  [{1,6}{2,5}{3,4}{4,3}{5,2}{6,1}]

Possibility for sum 8 on the 2 dies casted  = 5 [{2,6}{3,5}{4,4}{5,3}{6,2}]

The possibility of getting 7 or 8 when the dies are casted = 6+5 = 11

Total probability of getting a sum of 7 or 8 = $\bold{\frac{11}{36}}$.