JAMB - Mathematics (2007 - No. 9)
In how many ways can 6 subjects be selected from 10 subjects for an examination
218
216
215
210
Explicación
\(^{10}C_6 = \frac{10!}{(10-6)!6!}=\frac{10!}{4!6!}\\
=\frac{(10\times 9\times 8\times 7 \times 6!)}{4\times 3\times 2\times 1\times 6!}\\
=210\)
=\frac{(10\times 9\times 8\times 7 \times 6!)}{4\times 3\times 2\times 1\times 6!}\\
=210\)