Question

A recipe for a cake instructs you to bake it at 220° C for 45 minutes. How many degrees Fahrenheit is this?

Answer 1

This is an exercise on Thermometric scales.

We have as data:

• T = 220 °C
• T =  °F ??

We apply the following formula:

$\large\displaystyle\begin{gathered}\sf ^{\circ}F=\frac{9}{5}\ ^{\circ}C+32 \end{gathered}$

We substitute data in the formula:

$\large\displaystyle\begin{gathered}\sf ^{\circ}F=\frac{9}{5}\times220+32 \end{gathered}$

First multiply 9 x 220, then the result of this division is divided by 5.

$\large\displaystyle\begin{gathered}\sf =396+32 \ \ \to \ \ [Add] \end{gathered}$

$\boxed{\large\displaystyle\begin{gathered}\sf =428 \ ^{\circ}F \end{gathered}}$

Therefore the cake recipe that should be baked at 220 °C for 45 minutes, on the Fahrenteir scale is 428 °F. Which indicates that it will be very hot.