Total outcomes when a die is thrown 3 times: \[ n(S) = 6 \times 6 \times 6 = 216 \] Let \( A \) be the event: number \( > 4 \) occurs at least once. Numbers > 4 are: 5 and 6 \( \Rightarrow \) favorable outcomes = 2 So, let’s find complement event: no number > 4 That means all outcomes are from {1,2,3,4} So each roll has 4 options: \( 4^3 = 64 \) \[ P(A) = 1 - P(A') = 1 - \frac{64}{216} = \frac{152}{216} = \frac{19}{27} \] Final Answer: \[ \boxed{\frac{19}{27}} \]
The standard electrode potential for Ni²⁺/Ni couple is -0.25 V and for Ag⁺/Ag couple is 0.80 V. These two couples are connected to make an electrochemical cell. The redox reaction is spontaneous. The cell potential will be: