# Average Rate Problem: Solve for r=60mph

• carlodelmundo
In summary, the conversation discusses how to maintain an average speed of 40 mph on a trip when the initial half of the trip is completed at a speed of 30 mph. The solution involves using the equation d=rt and substituting the given values to solve for the remaining half of the trip. The result is a required speed of 60 mph to maintain an overall average of 40 mph.
carlodelmundo

## Homework Statement

Support you wish to average 40 mph on a trip and find that when you are half the distance to your distance to your destination you have averaged 30 mph. How fast should you travel in the remaining half of the trip to attain an overall average of 40 mph?

d = rt

## The Attempt at a Solution

I used S(avg) = x / (t1 + t2) = 40 mi/hr

I substituted (2d/60) for t1 and (d/2r) for t2.

Doing some algebraic manipulations, I got r = 60 mph. Is this correct?

carlodelmundo said:

## Homework Statement

Support you wish to average 40 mph on a trip and find that when you are half the distance to your distance to your destination you have averaged 30 mph. How fast should you travel in the remaining half of the trip to attain an overall average of 40 mph?

d = rt

## The Attempt at a Solution

I used S(avg) = x / (t1 + t2) = 40 mi/hr

I substituted (2d/60) for t1 and (d/2r) for t2.

Doing some algebraic manipulations, I got r = 60 mph. Is this correct?
Yes, and this is easy enough to check.

Thanks!

## 1. What is the formula for calculating average rate?

The formula for average rate is distance divided by time, expressed as rate = distance / time.

## 2. How do I solve for r in an average rate problem?

To solve for r in an average rate problem, you will need to have values for distance and time. Then, you can plug those values into the formula rate = distance / time. In this case, the value of r will be 60mph.

## 3. Can you provide an example of an average rate problem?

Here is an example: A car travels 300 miles in 5 hours. What is the average rate of the car? In this problem, the distance is 300 miles and the time is 5 hours. Plugging those values into the formula, we get rate = 300 miles / 5 hours = 60mph.

## 4. How do I convert the rate from mph to another unit?

To convert the rate from mph to another unit, you can use a conversion factor. For example, to convert to kilometers per hour (km/h), you can multiply the rate in mph by 1.60934. So, in our example, the rate in km/h would be 60mph x 1.60934 = 96.56 km/h.

## 5. What are some real-life examples of average rate problems?

Real-life examples of average rate problems include calculating the average speed of a car during a road trip, finding the average rate of a runner during a race, or determining the average rate of a chemical reaction in a laboratory experiment.

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