The main focus of this permutation & combination question is part (iii) where students are expected to follow a simple definition and solve the question. I have used the listing method which could be slightly longer but it is clearer for understanding for most students. This is the thinking process but there is certainly a shorter presentation to the listing method by considering general cases since this is a 5 marks question. I would love to hear from you on the shorter presentation, leave your working in the comments section.
Ai Ling Ong
Hi, I'm Ai Ling Ong. I enjoy coaching students who have challenges with understanding and scoring in 'A' Level H2 Maths. I develop Math strategies, sometimes ridiculous ideas to help students in understanding abstract concepts the fast and memorable way. I write this blog to share with you the stuff I teach in my class, the common mistakes my students made, the 'way' to think, analyze... If you have found this blog post useful, please share it with your friends. I will really appreciate it! :)