Watch comprehensive video reviews for most units, designed for final exam preparation. Each video includes integrated problems you can solve alongside detailed solutions.
Not your average video:
Interactive Problems: Solve problems alongside the video with step-by-step guidance and detailed solutions.
Exam Preparation: Complete unit reviews designed for final exam preparation with all key concepts covered systematically.
Expert Teaching: High-quality instruction from Perplex co-founder James Mullen with clear explanations, worked examples, and exam tips.
Not your average video:
Interactive Problems: Solve problems alongside the video with step-by-step guidance and detailed solutions.
Exam Preparation: Complete unit reviews designed for final exam preparation with all key concepts covered systematically.
Expert Teaching: High-quality instruction from Perplex co-founder James Mullen with clear explanations, worked examples, and exam tips.
Counting & Binomials
Watch comprehensive video reviews for Counting & Binomials, designed for final exam preparation. Each video includes integrated problems you can solve alongside detailed solutions.
Not your average video:
Interactive Problems: Solve problems alongside the video with step-by-step guidance and detailed solutions.
Exam Preparation: Complete unit reviews designed for final exam preparation with all key concepts covered systematically.
Expert Teaching: High-quality instruction from Perplex co-founder James Mullen with clear explanations, worked examples, and exam tips.
Not your average video:
Interactive Problems: Solve problems alongside the video with step-by-step guidance and detailed solutions.
Exam Preparation: Complete unit reviews designed for final exam preparation with all key concepts covered systematically.
Expert Teaching: High-quality instruction from Perplex co-founder James Mullen with clear explanations, worked examples, and exam tips.
The video will automatically pause when it reaches a problem.
AHL AA 1.10
Combinations are arrangements of items where order does not matter.
The number of ways of permuting r items from a set of n items is similar to the number of permutations, except that we do not care about the order of the r items. The number of ways to order r items is r!, so the number of combinations is
which is the binomial coefficient "nCr".
Example
How many different committees consisting of 4 members can be made from a class of 12 students?
AHL AA 1.10
Combinations are arrangements of items where order does not matter.
The number of ways of permuting r items from a set of n items is similar to the number of permutations, except that we do not care about the order of the r items. The number of ways to order r items is r!, so the number of combinations is
which is the binomial coefficient "nCr".
Example
How many different committees consisting of 4 members can be made from a class of 12 students?