The field strength midway between two parallel wires carrying equal currents in the same direction will be

ZERO

Explanation:

As we know that magnetic field due to a straight wire at some distance from the wire is given as

so here since we have to find the magnetic field at the mid point of two parallel wire having equal current in them

so we can say

and since it is mid of of two wires so all the parameters will be same but the direction would be reversed as the mid point lies on the right side of one wire and on the left side of other wire.

now net magnetic field at mid point will be

no. dot product   =0 when vecs at right angles

d₁ = displacement of tern from arctic to antarctic = 11000 miles

d₂ = displacement of tern from antarctic to arctic =   - 11000 miles

d = total displacement for the journey

total displacement for the journey is given as

d = d₁ + d₂

d = 11000 + (-11000)

d = 0 miles

t₁ = time of travel from arctic to antarctic = 3 months = 3 x 30 days = 90 days

t₂ = time of travel from antarctic to arctic = 3 months = 3 x 30 days = 90 days

t = total time of travel

total time of travel is given as

t = t₁ + t₂

t = 90 + 90

t = 180 days

average velocity is given as

average velocity = total displacement/ total time

v = d/t

v = 0/180

v = 0 miles/day