In this video, we are going to apply inverse variation.

First, let’s discuss direct variation. It is basically proportions.

**For example:**

The number of gallons of gasoline is proportion to the number of miles.

Inverse variation is the opposite of direct variation, where the increase of one meets the decrease of the other.

**For example:**

If it takes 2 hours for a 5-pound block of ice to melt in a 60-degree Fahrenheit room, how long will it take a 5-pound of ice to melt in an 80-degree Fahrenheit room, assuming time and temperature are inversely related.

First, let’s use the equation *t*_{1}T_{1}=t_{2}T_{2} where *t* is time, *T* is temperature

Substitute the values

Multiply

Divide *80* from both sides to isolate *x*

So it takes 1.5 hour for the ice to melt

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