A certain generating power plant requires 1 MW output. Two types of Diesel- engine installations are available. One unit is a low-speed unit that can operate on a low-grade fuel at 5.08 bar IMEP. The other two high-speed units can operate at 6.8 bar IMEP but require more refined fuel. If the ISFC (indicated specific fuel consumption) is 0.105 kg/kW-hr, if the fuel for the low-speed engine cost $288/ton and that for the high-speed engines is $320/ton, and if the friction mep is 1.22 bar in both cases, determine the fuel cost of the two installations in mills per kilowatt- hour?