question_answer 20)

A certain freezing process requires that room temperature be lowered from \[\text{4}0{}^\circ \text{C}\] a the rate of \[\text{5}{}^\circ \text{C}\] every hour. What will be the room temperature 10 hours after the process begins?

Answer:

                Room temperature 10 hours after the process begins \[=\text{4}0{}^\circ \text{C}-\text{1}0\times \text{5}{}^\circ \text{C}\] \[=\text{4}0{}^\circ \text{C}-\text{5}0{}^\circ \text{C}\] \[=-{{(50-40)}^{o}}\,C=-{{10}^{o}}C\]