I swear this means something

[kanzeon_2040]

30 = x*23.5 + (1-x)*43.07

30 = 43.07 + 23.5x - 43.07x

30 - 43.07 = x * (23.5 - 43.07)

x = (30 - 43.07) / (23.5 - 43.07)