Question

a boy leaves his house at 9:30 a.m. for his school the school is 2 km away and classes start at 10 a.m. she walks at a speed of 3 km per hour for the first kilometre,at what speed should you walk II km to reach just in time.

Answer 1

Distance=2km
Total time=30 min=0.5hr
u(initial speed)=3km/h for 1st 1km
Hence time taken=distance/speed=1/3h
Time left =0.5-1/3=0.5/3h
Distance left=1km
Hence,speed at which he should walk the 2nd km would be 1/0.5/3=6km/h

this is your answer..