Initial temperature of the liquid = 0 degrees.
Rate of changes of liquid temperature = -0.2 per minute.
Rate of change also represents slope of a linear function.
We know, slope-intercept form of a linear equation
y=mx+b, where m is the slope (rate of change) and b is y-intercept(initial temprature).
With respect to given problem, y represents temperature of a liquid after x number of minutes.
According to given problem, slope(rate of change) = -0.2 per minute and y-intercept(initial temprature)=0.
Plugging values of m and b in the above slope-intercept form of a linear equation.We get,
y=-0.2x+0
or y=-0.2x.
Final temprature is given -14.6 degrees and we need to find time when temprature reach -14.6 degrees.
As y represents temperature of a liquid , we need to plug y=-14.6 in above equation.
We get,
-14.6=-0.2x.
Dividing both sides by -0.2.
-14.6/-0.2=-0.2x/-0.2
x=73.
We got 73 minutes.
73 minutes can be convert in hours.
We have 60 minutes in an hour.
Therefore, 73 = 60+13.
So, 1 hour and 13 minutes will it for the liquid to reach -14.6 degrees.
In minutes answer is 73 minutes.