Problem: You are to drive to an interview in another town, at a distance of 330 km on an expressway. The interview is at 11:15 a.m. You plan to drive at 100 km/h, so you leave at 8:00 a.m. to allow some extra time. You drive at that speed for the first 120 km, but then construction work forces you to slow to 43.0 km/h for 43.0 km.
Part A: What would be the least speed needed for the rest of the trip to arrive in time for the interview?
I don't understand how to get the answer for above problem. Can you please help me with this problem?