Answer:

Distance d1=30km

speed s1= 60km/hr

time= 30/60 = 1/2hr

distance d2=30km

speed s2=40km/hr

time t2=30/40= 3/4hr

total time =t1+t2 =1/2+3/4=5/4hr

Distance, D1=30km

Speed s1=60km/hr

time=6030=21hr

Distance D2=30km

Speed s2=40km/hr

Time, t2=4030=43hr

Total time T=t1+t2=21+43=45hr=45∗60 min=75 min