Hi Ankur,

Let the force exerted be A and their effective pull be B.

Here, A = 20N, B = 20N, R = 30θ= ?

using R=√A^2 + B^2 + 2ABcosθ

Now, we have 30^2 = 20^2 + 2×20×20cosθ

or cosθ*30^2−20^2−20^2/2×20×20=0.125

or θ=82^249'.

Feel free to ask doubts in the Comment Section.

I hope this information helps you.

Good Luck!