How do I calculate time to steady state using half life of a drug?

A patient is diagnosed with hypertension and a drug, propranolol is prescribed – 40 mg three times a day. Propranolol has a half life of approximately 6 hours. After how many hours does propranolol reach steady state concentrations in the plasma?

For this I get 24-30 hours but then the question asks:

1) If propranolol is given at a dose of 60 mg twice a day – when would plasma steady state levels have been achieved? Would the potential for adverse effects be more or less with this regimen?

Also when

2) If 60 mg of propranolol had been administered 3 times a day what parameter would have changed? Time taken to reach steady state or the steady state level.