Question

Solve this:
5. The temperature at 12 noon was 10^o C above zero. If it decrease at the rate of 2^oC per hour until midnight, at what time would the temperature be 8^oC below zero? What would be the temperature at mid-night ?

Answer 1

Dear student,

$$\begin{gathered} 1.Letthetimebex \\ \Rightarrow 10-(-8)=x\times (-2),--[-2becauseitisdecreasing2°Ceveryhour] \\ \Rightarrow 18=x\times \left(-2\right) \\ \Rightarrow -\frac{18}{2}=x \\ \Rightarrow -9=x \\ neglecting-vesignastimecan\text{'}tbe-ve \\ Hence,at9:00pmthetemperaturewillbe-8°C. \\ 2.Letthetemperaturebex \\ \Rightarrow 10+12\times (-2)=x \\ \Rightarrow 10+(-24)=x \\ \Rightarrow -14=x \\ Thereforethetemperatureonmid-nightwillbe-14°C. \end{gathered}$$

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