Conversion of Degrees Celsius to Degrees Fehrenheit.
[tex]\begin{gathered} F(t)=\frac{9}{5}C(t)\text{ + 32 }\ldots eqn(1) \\ \text{Making C(t) the subject of the formula, we get} \\ \text{Subtract 32 from both sides, we get} \\ F(t)\text{ -32=}\frac{9}{5}C(t)+32-32 \\ F(t)\text{ -32 =}\frac{9}{5}C(t) \\ \text{Multiplying both sides by }\frac{5}{9}\text{ , we get} \\ \frac{5}{9}\lbrack F(t)-32\rbrack=\frac{5}{9}\times\frac{9}{5}C(t) \\ \\ \frac{5}{9}\lbrack F(t)\text{ - 32\rbrack = C(t)} \\ C(t)=\frac{5}{9}\lbrack F(t)\text{ -32\rbrack}\ldots eqn(2) \end{gathered}[/tex]
Substitute 12 for t in eqn(1), we get
[tex]\begin{gathered} t=12 \\ C(12)=40 \\ F(12)=\frac{9}{5}C(12)\text{ + 32} \\ F(12)=(\frac{9}{5}\times40)\text{ }+32 \\ F(12)=(9\times8)+32 \\ F(12)=72+32=104^oF \end{gathered}[/tex]
When t =24,
C(24) = 0 , ( does not exist since the graph did not touch the graph)
[tex]\begin{gathered} t=24 \\ C(24)=0 \\ F(24)=\frac{9}{5}C(24)\text{ + 32} \\ F(24)=(\frac{9}{5}\times0)\text{ +32} \\ F(24)=32^oF \end{gathered}[/tex]
Hence, the correct answer are:
t =12, C(12) = 104 degrees Fehrenheit, and
t =24, C(24) = 32 degrees Fehrenheit