Percent Increase/Decrease
📚 What You'll Learn
- Understanding how rates change with different obstacles
- Using a model to find a percentage of a standard rate
- Calculating percent increase (adding to the original)
- Calculating percent decrease (subtracting from the original)
In this video, let's take a look at how to calculate percent increase and decrease.
This red object, it travels at a standard rate of 12 minutes per unit.
However, when it encounters obstacles like water, the rate changes.
When passing through water, the number of minutes needed to travel each unit increases by 50 percent. If the number of minutes increase, that means the object is taking more time. It is moving slower.
So how long will the object take to travel across water? Well, I'm going to use a model to help me figure that out.
This 12 minutes represents 100 percent I can use the model to help show 50 percent. That's one-half and it corresponds to six minutes.
In this scenario, the time is increasing by 50 percent, which means the red object will take 18 minutes to travel that one unit across water.
When moving across rolling hills, the number of minutes needed to travel each unit decreases by 25 percent from the standard rate. That means it's moving faster.
Once again, I'm going to use the model to help me figure out how long the object will take to travel across hills. Remember, 12 minutes corresponds to 100 percent.
25 percent is one-fourth of that. And it corresponds to three minutes.
In this scenario, the number of minutes is decreasing, so the object will take nine minutes to travel across rolling hills.
And that's how to find percent increase and decrease from a standard rate.