A body A, of mass m=0.1 kg has an initial velocity of 3i ms⁻¹. It collides elastically with another body, B of the same mass, which has an initial velocity of 5 j ms⁻¹. After collision, A moves with a velocity →v=4(i+j). The energy of B after collision is written as x/10 J. The value of x is _____.