Answer:
s(2v₁+v₂+v₃)/4
Step-by-step explanation:
Recall that relationship between speed,distance and time is expressed as
speed=distance/time.
For the first part of the journey travelled at a speed of V₁ and covered a distance of (s/2), the time taken t₁=(s/2)/v₁
for the second part of the journey,let the time taken to complete both half of the second journey be t₂ and t₃ respectively. since it travel each half each distance at equal half time,then
t₂₌t₃
let the distance of the second journey be (s/2), where each time complete (s/4) distance. the time taken is
t₂₌(s/4)/v₂ and t₃=(s/4)/v₃
hence the total time taken is to cover the distance s is
t=t₁+t₂+t₃
t=(v₁s/2)+ (v₂s/4)+(v₃s/4)
t=s(2v₁+v₂+v₃)/4