Two short bar magnets of length $1 \mathrm{cm}$ each have magnetic moments $1.20 \mathrm{A}{ \mathrm{m}}^2$ and $1.00 \mathrm{A}{ \mathrm{m}}^2$ respectively. They are placed on a horizontal table parallel to each other with their $\mathrm{N}$ poles pointing towards the South. They have a common magnetic equator and are separated by a distance of $20.0 \mathrm{cm}$. The value of the resultant horizontal magnetic induction at the mid-point $O$ of the line joining their centres is close to $n\times {10}^{-4} \mathrm{Wb}/{\mathrm{m}}^2$. Then the value of $n$ is

(Horizontal component of earth's magnetic induction is $3.6\times {10}^{-5} \mathrm{Wb}/{\mathrm{m}}^2$ )