Each of four machines is to be assigned to one of five possible locations. the objective is to assign the machines to locations that will minimize the materials handling cost. the machine–location costs are given in the following matrix. find the optimal assignment.

Ahe-xe mixture containing a 0.75 mole fraction of helium is used for cooling electronics in an avionics application. at a temperature of 300 k and atmospheric pressure, calculate the mass fraction of helium and the mass density, molar concentration and molecular weight of the mixture. if the cooling capacity is 10 l, what is the mass of the coolant?