A boy runs along a straight path for the first half distance with a velocity V₁ and second half with velocity V₂. The mean velocity V is given by

(a) 2/v = 1/v₁ + 1/v₂

(b) v= v₁+ v₂/2

(c) V= √(v₁.v₂)

(d) V₁ + V ₂