Answer: His room's temperature is 20°C.
Explanation:
Since we have given that
Temperature at which water boils = 100°C
According to question, it is 400% more than his room's temperature.
Let his room temperature would be 'x'.
So, our equation becomes,
![(100+400)/(100)* x=100\\\\(500)/(100)* x=100\\\\5x=100\\\\x=(100)/(5)\\\\x=20^\circ C](https://img.qammunity.org/2020/formulas/mathematics/middle-school/pa8gkamib2fjzddhl7gi607dza3zwz3brr.png)
Hence, his room's temperature is 20°C.