Let's denote:
- d: Distance covered on packed dirt (meters)
- 4d: Distance covered on grass (meters) (since grass distance is four times packed dirt distance)
From the problem statement:
1. She covered both distances in a total of 21 minutes.
2. Speed on packed dirt = 201 meters per minute
3. Speed on grass = 100.5 meters per minute
We can set up the following equations based on time and distance:
For packed dirt:
d / 201
For grass:
4d / 100.5
Since the total time spent on both terrains is 21 minutes:
d / 201 + 4d / 100.5 = 21
Let's solve for d:
d / 201 + 4d / 100.5 = 21
To simplify, find a common denominator (which is 201):
d / 201 + 8d / 201 = 21
9d / 201 = 21
Multiply both sides by 201 to solve for d:
9d = 21 * 201
9d = 4221
d = 4221 / 9
d = 469
So, the distance covered on packed dirt is d = 469 meters.
Now, the distance covered on grass is 4d = 4 * 469 = 1876 meters.
Therefore, the distances covered are:
- Distance covered on packed dirt (meters): 469
- Distance covered on grass (meters): 1876