Question

a motor vehicle travelled the first one third of a distance at a speed of v1=10kmph,second one third at a speed of v2=20kmph and the last one third at a speed of v3=60kmph. determine the mean speed of the vehicle over the entire distance
a)15kmph
b)12kmph
c)10kmph
d)18kmph

Answer 1

v1 = 1/3 ×10 =10/3
v2= 1/3 ×20 = 20/3
v3=1/3×60 =60/3
mean= v1+v2+v3/3
10/3 +20/3 +60/3/3
90/3/3
30/3
10kmph
mean speed=10kmph
option c is answer