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Can somebody explain how the answer is this? M3

A particle P of mass 0.2kg is attached to fixed points A and B on a smooth horizontal table by two light elastic strings, each of natural length 0.3 metres and modulus of elasticity 12 newtons. The distance AB is 1 metre, and O is the mid-point of AB. The particle is projected horizontally from O towards B with initial speed 2 ms^-1. At time t seconds after the projection, the displacement of P from O towards B is x metres and both strings are taut. Show that the tension in the string is (8-40x) newtons, and find the corresponding expression for the tension in the string PA.

So I found the tension OB to be the stated expression by essentially just letting extension = (0.2 - x) and using the formula for tension. But I honestly can't find the expression for the 2nd string PA... Any help for the method would be appreciated.