Question

meenu drives her car 3/2 hours with the constant speed of 66 km/hr and then for another 45 mintues with a constant speed 80km/hr. What her was average speed ?

Answer 1

time1=3/2×60=1hr and 30min
time 2=45 min
average speed=total distance/total time
average speed=66×3/2+80×3/4
-----------------------
2-15
=99+60
------------
135
159/135=1.44(approx)

Answer 2

For 1st destination

Speed = 66km/h

Time=3/2h

Distance =speed ×time

=66×3/2=99 km

For 2nd destination

Speed =80km/h

Time=45m=3/4h

Distance =speed × time =89×3/4=60km

Average speed = total distance /total time.

(99+60)/(3/2+3/4)

=159/(9/4)=(159×4)/9=636/9

70.67km/h