There is some disparity in the quality of education among the various races and provinces in South Africa. Since the dawn of democracy in 1994, the government has tried to bridge the gap using quintile categorisation of public schools and its concomitant funding. The categorisation is based on the socioeconomic status of the community in which the schools are located. This study investigated the achievement of learners in the first four quintiles from one school district on the topic of probability. The study employed a quantitative research approach and used Bloom's taxonomy as the conceptual framework. A total of 490 Grade 12 learners from seven schools participated in the study. Results showed that learners in Quintile 4 had significantly higher achievement scores than learners in the lower quintiles at all levels of Bloom's taxonomy except synthesis. Counter intuitively, Quintile 1 students had higher achievement than those in Quintiles 2 and 3 at all cognitive levels of Bloom's taxonomy, with the exception of synthesis. The educational implications of the findings are discussed in relation to quintile ranking of schools and learner achievement.