Exercise · ZW-MULTIPLICATION-PRINCIPLE-001 · ★☆☆ Basic

A shop offers 4 different shirts and 3 different pairs of trousers. In how many ways can an outfit with one shirt and one pair of trousers be put together?

Choose one option.

Show answer
  • B. \(12\)

Explanation

There are 4 choices for the shirt and, for each, 3 for the trousers: \(4\cdot 3=12\). Adding (7) confuses this with the sum rule.

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Review the concept: Multiplication principle

If a task is done in successive steps and step \(i\) admits \(n_i\) options regardless of how the earlier steps were done, the total number of ways \(N\) is the product of those numbers.

\[N=n_1\cdot n_2\cdots n_k\]

More practice problems: multiplication principle

ZW-MULTIPLICATION-PRINCIPLE-002 →