A steam-electric power plant delivers 900 MW of electric power. The surplus heat is exhausted into a river with a flow of 4.17105 kg/s, causing a...

A steam-electric power plant delivers 900 MW of electric power. The surplus heat is exhausted into a river with a flow of 4.17×105 kg/s, causing a change in temperature of 1.13 oC. What is the efficiency of the power plant (in % Don't enter a unit.)? What is the rate of the thermal source?      Please show work and include formulas used.