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 2/5 minutes. What was the change in temperature each minute?

Answer 1

First, let's convert the fraction, to decimal by dividing:

2/5 = 0.4

So, time is 5.4 mins

It goes from 100 to 19 in 5.4 mins

Change is: 100 - 19 = 81 degrees

Thus,

81 degree change in 5.4 minutes.

To get change in temp EACH minute, we divide by total number of minutes, so

81/5.4 = 15

So,

15 degree change (decrease) in each minute (rate)