At 7 o'clock Hoa rides a motorbike from A to B at a speed of 30 km/h and arrives at B at 11 o'clock. An took a car to depart from A but arrived 15 minutes after Hoa and arrived at B 10 minutes before Hoa. Calculate:a) The length of the distance ABb) Speed of Anc) To reach B at the same time as Hoa, with what speed must An go?

It equals just about 6,300 km per hour each day an week

Tons?

Distance covered = speed x timethe distance traveled going against the stream = distance traveled with the stream.therefore it is the speed and the time that are the variables.as he travels the same distance both ways, speed x time is the same for each way.going upstream his speed is 4 kph; going downstream his speed is 6 kph.therefore we have two simultaneous equations: time upstream x 4 = time downstream x 6time upstream + time downstream = 60 minutestherefore we have the equation: time upstream = 6/10 hour, time downstream therefore = 4/10 hour.distance traveled at 4km/hr in 6/10 hour = 24/10 = 2.4km.check: distance traveled at 6km/hr in 4/10 hour = 24/10 = 2.4km.