A coal fired steam power plant is to be designed for the purpose of generating electrical power for a city with a population of 60,000 residents. Based on an order-of-magnitude analysis, it is estmiated that each resident will consume an average energy of 55MJ per day. The coal-fired boilder supplies 70 MW to the steam while thermal energy is rejected to a nearby lake whos average temperature is 15 C. What is the minimum required temperture of the boiler to meet the power demands of the city?