Because of road construction in one city commuters were advised to plan their Monday morning commute would take 150% of thier usual time. How do I solve this problem

The usual amount of time is 100%. 50% is half of the amount of time. So 150% is the usual time plus half the usual time. So if it normally takes an hour, they should plan on it taking an hour and a half. If the usual amount of time is ten minutes, they should plan on it taking 15 minutes.