Please help me answer this with clear solutions.?

Jane drives her car at 20kph for 40 km and 40 kph for the next 60 km . What is her average speed for the entire trip?Please help me answer this with clear solutions.?
= (40 + 60)/(40/20 + 60/40)


= 100/(2 + 3/2)


= 100/(4/2 + 3/2)


= 100/(7/2)


= 100(2/7)


= 200/7 or 28 4/7





Answer: 28 4/7 or 28.57 1/7 kilometers per hour (kph)





Driving time in hours:


= 40 km/20 kph + 60 km/40 kph


= 2 hrs + 3/2 hrs


= 4/2 hrs + 3/2 hrs


= 7/2 hrs or 3 1/2 hrs





Distance covered in kilometers:


= 40 km + 60 km


= 100 km





Proof (distance = rate * time):


100 km = 28 4/7 kph * 3 1/2 hrs


100 km = 200/7 kph * 7/2 hrs


100 km = 1,400/14 km


100 km = 100 kmPlease help me answer this with clear solutions.?
Using the weighted-average method,





Average speed = [(40 * 20) + (40 * 60)]/(40 + 60)





Average speed = (800 + 2400)/(100)





Average speed = 3200/100





Average speed = 32 kph





Hope this helps.
average speed is equal to total distance divide total time. We already know total distance: 40+60=100. The time for the first part will be 2 hours, and for the second part it would be 1.5 (One and a half) hours so it is 100/3.5 which is about 28. Thanks hope i helped
Elapsed time for each leg of the trip





20kph for 40 km: 2 hrs





40 kph for the next 60 km: 1.5 hrs





d = rt {we know d %26amp; t}





r = d/t = (40 + 60)/(2 + 1.5) = 100/3.5 = 28.57 {average rate}