Question

a car travels 50 kilometre per hour for 30 minutes 40 km per hour for the next 15 minutes and then 60 kilometre per hour for the next 60 minutes calculate the average speed of a car​

Answer 1

Answer: 54.28km/hr

Explanation:

V1=50km/hr

t1=30min=30/60=1/2hrs

∴S1=V1×t1=50×1/2=25km

V2=40km/hr

t1=15min=15/60=1/4hrs

∴S2=V2×t2=40×1/4=10km

V3=60km/hr

t2=60min=60/60=1hr

∴S3=V3×t3=60×1=60km

∴Average Speed=Total Distance/Total Time

                            =S1+S2+S3/t1+t2+t3

                            =25km+10km+60km/(1/2hrs)+(1/4hrs)+(1hrs)

                            =95km/(7/4hrs)

                            = 380/7km/hr

                            =54.28km/hr