JAMB Mathematics 2014 Paper

Concept:Probability is the ratio of favourable outcomes to the total possible outcomes in the sample space.Explanation:The numbers chosen are from 10 to 30 inclusive.So the total number of possible outcomes is $n(S) = 30 - 10 + 1 = 21$.Let $E$ be the event that the chosen number is divisible by 3.The multiples of 3 between 10 and 30 are $12, 15, 18, 21, 24, 27, 30$.Therefore, $n(E) = 7$.Probability of $E$ is given by:$P(E) = \frac{n(E)}{n(S)} = \frac{7}{21}$.Simplifying: $P(E) = \frac{1}{3}$.Answer:$\frac{1}{3}$ (Option C).