Puan Halimah telah merancang tiga aktiviti untuk ahli-ahli Kelab Robotik di SMK Damai. Set A = {ahli yang menyertai Line Follower}, Set B = {ahli yang menyertai Robot Arm} dan Set C = {ahli yang menyertai Drone Coding}. Rajah menunjukkan gambar rajah Venn bagi ketiga-tiga set itu dengan set semesta ξ = A ∪ B ∪ C. Setiap huruf atau nombor yang ditulis dalam sesuatu kawasan mewakili bilangan ahli dalam kawasan itu: p bagi A sahaja, q bagi A ∩ B, 24 bagi B sahaja, 6 bagi B ∩ C dan r bagi C sahaja. Tiada ahli yang menyertai Line Follower dan Drone Coding serentak. Diberi bahawa p = 23, q = 15 dan r = 26. Cari bilangan ahli yang menyertai tepat satu daripada ketiga-tiga aktiviti itu.

Puan Halimah planned three activities for the members of the Robotics Club at SMK Damai. Set A = {members who joined Line Follower}, Set B = {members who joined Robot Arm} and Set C = {members who joined Drone Coding}. The diagram shows a Venn diagram for these three sets, where the universal set is ξ = A ∪ B ∪ C. Each letter or number placed in a region gives the number of members in that region: p is for A only, q is for A ∩ B, 24 is for B only, 6 is for B ∩ C and r is for C only. No member joined both Line Follower and Drone Coding. It is given that p = 23, q = 15 and r = 26. Find the number of members who joined exactly one of the three activities.