Note that 2n° & the opposite angle of 2n° (vertical angle) are congruent, let's call it angle A, so A°=2n°
We also notice that angle A° + (n+18)° = 90°
Solve for n:(don't forget that A° =2n°) ==> 2n° + (n + 18)° = 90°,
3n° = 90°-18° ==> 3n° = 72° and n° = 24°
So if n=24°, 2n=48°
