CAPE Pure Mathematics Unit 2 · May/June 2015 · Paper 1 · Question Q39

The letters of the word I R R E G U L A R are to be arranged in a line. The number of possible arrangements in which the 3 Rs are NOT together is

1. (A)7!
2. (B)\frac{9!}{3!} - 7!
3. (C)9! - 7!
4. (D)9! - 7! \times 3!