WAEC - Further Mathematics (2007 - No. 27)
How many ways can 12 people be divided into three groups of 2, 7 and 3 in that order?
7920
792
187
42
คำอธิบาย
= \(\frac{12!}{2! 3! 7!} \)
\(\frac{12 \times 11 \times 10 \times 9 \times 8 \times 7!}{2 \times 3 \times 2 \times 7!}\)
= \(7,920\)