Given, velocity of train w.r.t. the earth,
vT→E=80km∕h .......(i)
Velocity of the man w.r.t. the train,
vM→T=−10km∕h .......(ii)
Velocity of the plate w.r.t. the man,
vP→M=−20km∕h ........(iii)
Velocity of the spider w.r.t. the plate,
vS→P=5km∕h .......(iv)
From Eqs. (i), (ii), (iii) and (iv), we get
∴ The velocity of the spider w.r.t. the earth,
vS→E=VS→P+VP→M+VM→T +VT→E =5−20−10+80 =55km∕h (towards Hubli)