JAMB Mathematics 2023 Paper

Concept:Probability is the number of favourable outcomes divided by the total number of possible outcomes.Explanation:When a coin is thrown 3 times, each throw gives either head $H$ or tail $T$.So the total number of possible outcomes is $2 \times 2 \times 2 = 8$.The sample space is $\{HHH, HHT, HTH, THH, TTH, THT, HTT, TTT\}$.The event "at least one head" includes every outcome except the single outcome with no head, which is $TTT$.Thus, favourable outcomes $= 8 - 1 = 7$.Therefore, $P(\text{at least one head}) = \frac{7}{8}$.Answer:$\frac{7}{8}$ (Option A).