Two fixed points, A and B, are such that A is 4m vertically above B. A light spring of natural length 1.5 m is attached to A, and at the other end it has a particle of mass 6 kg attached. A second light spring of natural length 1 m is attached to the point B. Its other end is attached to the same particle. Both springs are in the same vertical plane. Given that the modulus of elasticity of the lower spring is one-third of that of the upper spring, and that the extension of one spring is six times the compression of the other spring, find the modulus of elasticity of the lower spring.