Factory A produces a solution of 40% concentration of chemical Y at a rate of 7kg/min, while factory B produces a solution of 20% concentration of chemical Y at a rate of 4kg/min. Both solutions are fed into a mixer containing 60kg of a 25% concentration solution of chemical Y. The mixture leaves the mixer at a rate of 10kg/min. Assuming uniform mixing, what will be the concentration of chemical Y in the final solution after 20 minutes