Six faces have numbers {1,2,3,5,7,11}. Sum of the numbers on top faces of both the sides is less than or equal to 8 =(1,1),(1,2),(1,3),(1,5),(1,7)→5 (2,1),(2,2),(2,3),(2,5)→4 (3,1),(3,2),(3,3),(3,5)→4 (5,1),(5,2),(5,3)→3 (7,1)→1 n(S)=5+4+4+3+1=17 n(T)=6×6=36 ∴ Probability =