Flok

1) ke = .05 + 1.5(.11-.05) = .14 (CAPM)
WACC = (.3)(.09)(1-.35) + (.14)(.7) = 11.56%
Wd kd (1-t) ke We
2) ke = .18 (given in last paragraph of question)
WACC = (.3)(.09)(1-.35) + (.18)(.7) = 14.36%

The only thing that changes is the cost of equity, since the capital structure stays the same (70% equity 30% debt). I'm hoping that is all you wanted to know because I can't really give you a better explanation why.