Question

Obtain the values of the following:

(1) ²⁵C₂₃

(2) ⁸C₈

Answer 1

(1) ²⁵C₂₃

ⁿC_r = \(\frac{n!}{r!(n−r)!}\)

∴ ²⁵C₂₃ = \(\frac{25!}{23!(25−23)!}\)

= \(\frac{25!}{23!2!}\)

= \(\frac{25×24×23!}{23!×2×1}=\frac{600}{2}\) = 300

(2) ⁸C₈

ⁿC_r = 1

∴ ⁸C₈ = 1