Question

A certain freezing process requires that room temperature be lowered from 40°C at the rate of 5°C every hour. What will be the room temperature 10 hours after the process begins?

• A. ${11}^{\circ }C$
• B. $-{11}^{\circ }C$
• C. ${10}^{\circ }C$
• D. $-{10}^{\circ }C$

Answer 1

The correct option is D $-{10}^{\circ }C$

Initial temperature = ${40}^{\circ }C$
Change in temperature per hour = $-5^{\circ }C$
Change in temperature after 10 hours $=(-5)\times 10=$ $-{50}^{\circ }C$
∴The final room temperature after 10 hours of freezing process = (${40}^{\circ }C$ + $-{50}^{\circ }C$) = $-{10}^{\circ }C$