In an experiment, a solution of hydrochloric acid is to be kept between 30∘30^{\circ} and 35∘35^{\circ} Celsius. What is the range of temperature in degree Fahrenheit if conversion formula is given by C=59( F−32)\mathrm{C}=\frac{5}{9} \quad(\mathrm{~F}-32), where C\mathrm{C} and F\mathrm{F} represent temperature in degree Celsius and degree Fahrenheit, respectively.

Answer: The range of temperature in degree Fahrenheit is between 86∘F86^{\circ}F and 95∘F95^{\circ}F.

Step-by-step solution

Step 1: Set up the inequality for Celsius temperature

The problem states that the temperature in Celsius, denoted by CC, must be kept between 30∘30^{\circ} and 35∘35^{\circ}. This can be written as a compound inequality.

Step 2: Substitute the conversion formula

We are given the conversion formula C=59(F−32)C = \frac{5}{9}(F-32). We substitute this expression for CC into the inequality to relate the Fahrenheit temperature FF to the given Celsius range.

Step 3: Multiply by the reciprocal to isolate (F−32)(F-32)

To isolate the term (F−32)(F-32), we multiply all parts of the inequality by the reciprocal of 59\frac{5}{9}, which is 95\frac{9}{5}. This operation maintains the direction of the inequality signs because we are multiplying by a positive number.

Step 4: Simplify the inequality

Now, we perform the multiplication on both sides of the inequality. 30×95=6×9=5430 \times \frac{9}{5} = 6 \times 9 = 54 and 35×95=7×9=6335 \times \frac{9}{5} = 7 \times 9 = 63.

Step 5: Add 32 to all parts to find the range of F

To find the range of FF, we add 3232 to all parts of the inequality. This isolates FF and gives us the temperature range in Fahrenheit.

Step 6: Calculate the final Fahrenheit range

Performing the addition, we get 54+32=8654 + 32 = 86 and 63+32=9563 + 32 = 95. Thus, the temperature in Fahrenheit must be between 86∘86^{\circ} and 95∘95^{\circ}.

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