Question

In an experiment, a solution of hydrochloric acid is to be kept between $30^{\circ }$ and $35^{\circ }$ Celsius. What is the range of temperature in degree Fahrenheit if conversion formula is given by $C=\frac{5}{9}\left(F-32\right)$, where $C$ and $F$ represent temperature in degree Celsius and degree Fahrenheit, respectively?

• A. $86{}^{\circ }F$ to $96{}^{\circ }F$
• B. $86{}^{\circ }F$ to $95{}^{\circ }F$
• C. $36{}^{\circ }F$ to $42{}^{\circ }F$
• D. $85{}^{\circ }F$ to $95{}^{\circ }F$

Answer 1

Answer: (B)

It is given that $30<C<35$.
Putting $C=\frac{5}{9}\left(F-32\right)$, we get $30<\frac{5}{9}\left(F-32\right)<35$
or $\frac{9}{5}\left(30\right)<\left(F-32\right)<\frac{9}{5}\times \left(35\right)$
or $54<\left(F-32\right)<63$ or $86<F<95$.
Thus, the required range of temperature is between $86^{\circ }F$ and $95^{\circ }F$.