WAEC Mathematics 2016 Paper

Concept:Probability is found by dividing the number of favourable outcomes by the total number of possible outcomes.Explanation:When a die is thrown twice, the first and second throws are independent events.The total number of possible ordered outcomes is $6 \times 6 = 36$.The complete sample space is shown below.We need the sum of the two scores to be at least $10$, that is $10$, $11$, or $12$.The favourable ordered outcomes are $(4,6)$, $(5,5)$, $(6,4)$, $(5,6)$, $(6,5)$ and $(6,6)$.Counting them gives $n(E) = 6$.So the required probability is $\frac{n(E)}{n(S)} = \frac{6}{36}$.On simplification, $\frac{6}{36} = \frac{1}{6}$.Answer:Option B: $\frac{1}{6}$