Question

Выберите ответ:
256
196
225
289

Answer 1

Aₐᵇ = a! / (a - b)!

A₂₀⁶ = 20! / (20 - 6)! = 20! / 14!

A₂₀⁵ = 20! / (20 - 5)! = 20! / 15!

A₂₀⁴ = 20! / (20 - 4)! = 20! / 16!

1 / A₂₀⁴ = 16! / 20!

A₂₀⁶ + A₂₀⁵ = 20! / 14! + 20! / 15! = 20!*(15/15! + 1/15!) =16 * 20! / 15!

(A₂₀⁶ + A₂₀⁵) /  A₂₀⁴ = 16*20!/15! *  16! / 20! = 16*16 =  256