Question

Find n if ²³C_3n = ²³C_2n+3 

Answer 1

²³C_3n = ²³C_2n+3 

We know that if ⁿC_x = ⁿC_y, then x = y or x + y = n

∴ 3n = 2n + 3 or 3n + 2n + 3 = 23

∴ n = 3 or 5n = 20

∴ n = 3 or n = 4.