Question

kareem heats a beaker of water to a boil. then he records that the water temperature decreases from 100°c to 19°c in 5\frac{2}{5} minutes. what was the change in temperature each minute? enter your answer in the box.

Explanation:

Step1: Calculate total temperature change

The initial temperature is $100^{\circ}C$ and the final temperature is $19^{\circ}C$. The total temperature change $\Delta T$ is $100 - 19=81^{\circ}C$.

Step2: Convert time to improper - fraction

The time $t = 5\frac{2}{5}$ minutes. Convert it to an improper fraction: $t=\frac{5\times5 + 2}{5}=\frac{27}{5}$ minutes.

Step3: Calculate temperature change per minute

To find the change in temperature per minute, we divide the total temperature change by the total time. Let $x$ be the change in temperature per minute. Then $x=\frac{\Delta T}{t}=\frac{81}{\frac{27}{5}}$. Using the rule of dividing by a fraction ($a\div\frac{b}{c}=a\times\frac{c}{b}$), we have $x = 81\times\frac{5}{27}=15^{\circ}C$ per minute.

Answer:

$15^{\circ}C$