Two simple harmonic motion, are represented by the equations ${y_1} = 10\sin \left( {3\pi t + {\pi \over 3}} \right)$ ${y_2} = 5(\sin 3\pi t + \sqrt 3 \cos 3\pi t)$ Ratio of amplitude of y₁ to y₂ = x : 1. The value of x is ______________.