Question

Bus Travels 45 km at a uniform speed of 60 km per hour and 30 km at 40 km per hour calculate the average speed

Answer 1

time taken for 45 km=45/60=3/4hr
time taken for 30km=30/40=3/4hr
total time =6/4=3/2=1.5hr
total distance =45+30=75km
average speed =75/1.5=50km/hr

Answer 2

speed 1 = 60kmph
distance 1= 45 km
time 1=45/60
=3/4 h
speed 2= 40kmph
distance 2 =30 km
time 2= 30/40=3/4h
average speed= total distance/ total time
=45+30/3/4+3/4
=75/ 6/4=75/3/2
75/1.5= 750/15
=50 kmph
therefore the average speed is 50 kmph