Q.

One die has two faces marked 1, two faces marked 2, one face marked 3 and one face marked 4. Another die has one face marked 1, two faces marked 2, two faces marked 3 and one face marked 4. The probability of getting the sum of numbers to be 4 or 5, when both the dice are thrown together, is          [2025]

1 12  
2 23  
3 49  
4 35  

Ans.

(1)

Let x be the number shows on dice –1 and y be the number shows on dice –2.

Favorable outcomes = {(x, y) = (1, 3), (3, 1), (2, 2), (2, 3), (3, 2), (1, 4), (4, 1)}

   Required probability

                        =26×26+16×16+26×26+26×26+16×26+26×16+16×16

                        =1836=12.