+239 A car travels 40 kph for 20 kilometers, 50 kph for 25 kilometers, 60 kph for 45 minutes and 48 kph for 15 minutes. What is the average speed of the car, in kph?
Total distance = 20 + 25 + 45 + 12 = ..... km
Total time = .5 hr + .5 hr + .75 hr + .25 hr = .......... hrs
avg speed = (total distance) / ( total time ) = ........ km/ hr
+538 So the car travels 20+25+(60*45/60)+(48*(15/60) kilometers, or 20+25+45+12=102 kilometers.
Going at 40kph in one hour would get you 40 kilometers, so half of that time is needed for 20 kilometers. Same for the 50kph for 25 kilometers.
30+30+45+15 is 120. But our answer has to be in kilometers per hour, minutes would not work. So 120/60 is 2.
92/2 is an average of 51 Kph
