Question

A certain freezing process requires that room temperature be lowered from $40$ degree Celsius at rate of $5$degree Celsius every hour what will be the room temperature $10$hours after the process begins?

Answer 1

Let us assume that the lowered temperature is negative,

Initial temperature$=40°C$

Change in temperature per hour $=-5°C$

Change in temperature after $10$hours $=-5\times 10=-50°C$

∴The final room temperature after $10$hours of freezing process $=40°C+(-50°C)$

$=-10°C$

Therefore, the room temperature $10$ hours after the process begins$=-10°C$