JAMB Mathematics 2023 Paper

Concept:Probability is the ratio of favourable outcomes to total possible outcomes.Explanation:Total outcomes when two dice are tossed: $6 \times 6 = 36$.Prime sums possible are $2, 3, 5, 7,$ and $11$.Count the favourable outcomes for each prime sum:Sum $= 2$: $(1,1)$ gives $1$ outcome.Sum $= 3$: $(1,2), (2,1)$ gives $2$ outcomes.Sum $= 5$: $(1,4), (2,3), (3,2), (4,1)$ gives $4$ outcomes.Sum $= 7$: $(1,6), (2,5), (3,4), (4,3), (5,2), (6,1)$ gives $6$ outcomes.Sum $= 11$: $(5,6), (6,5)$ gives $2$ outcomes.Total favourable outcomes $= 1 + 2 + 4 + 6 + 2 = 15$.Thus, $P = \frac{15}{36} = \frac{5}{12}$.Answer:$\frac{5}{12}$ (Option A).