The research was aimed at investigating whether the intended time of 280 min per week for 92 weeks was adequate for the treatment of Senior High School (SHS) Elective Mathematics. A stratified random sampling method was used to select three sex female, two single sex male and three mixed SHSs in eight sub-metros in the Kumasi Metro of the Ashanti region of Ghana. The study involved 840 students and 36 Elective Mathematics teachers. A questionnaire on estimation of time and three achievement tests in Mathematics were used to collect the data. The data were analysed by mean of simple proportion, t-statistic and OneWay Analysis of Variance (ANOVA). Fisher's procedure was used to make pair-wise comparison among a set of three treatment means. The findings revealed that there is the need to increase treatment duration for elective mathematics as the intended time of 280 min per week for 92 weeks is inadequate. It was also found that teacher experience exhibits differences in treatment duration. Based on the findings, it was recommended that the intended time per week for SHS Elective Mathematics programme should be increased.