Peter and Tom shared the driving on a certain trip. If Peter and Tom both drove for the same amount of time, but Peter only drove \small \frac{2}{5} of the total distance, what was the ratio of Peter’s average speed to Tom’s average speed?

2:3

Explanation:

Now, Peter and Tom both drove for the same amount of time, t

If Peter only drove 2/5 of the total distance,

Then Distance driven by Tom

= 1-2/5=3/5

Speed= Distance/Time

Let x be the total distance

Peter's Average Speed=2x/5t

Tom's Average Speed=3x/5t

Ratio of Peter's Average Speed to Tom's Average Speed then is:

2x/5t : 3x/5t

Since the denominators are the same, we have

2x:3x

and cancelling out the x on both sides

The ratio of their average speed is 2:3

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