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?
NCERT Class 7th Mathematics Chapter 1 Integers

Answer 1

Initial Temperature = 40° C
Rate of change in temperature = 5°C/hour
Time = 10 hours

So, in 10 hours the temperature would be decreased by 10*5 = 50°C.

So, Final Temperature = 40 - 50  =  - 10°C

Answer 2

Given; A certain freezing process requires that room temperature be lowered from 40°C at the rate of 5°C every hour.

To Find; What will be the room temperature 10 hours after the process begins

Solution; It is given that A certain freezing process requires that room temperature be lowered from 40°C at the rate of 5°C every hour.

Room temperature of the place =40°C

Decrease in-room temperature=5°C

Time required=10 hours

Final temperature=40-10*5=-10

Hence the final temperature is -10°C