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\begin{array}{rlr} \dfrac{1}{3} x & =-3 x+60 & \\ \dfrac{10}{3} x & =60 & \\ 10 x & =180 & \\ x & =18 & \text{Substitute this back into} \, W(x).\\ y & =W(18) & \\ & =\dfrac{1}{3}(18) & \\ & =6 \end{array}