3. Luna walked around a rectangular courtyard twice in three minutes and twenty seconds. She walked along each shorter side of the courtyard for 15 s. How long did she walk along each longer side of the courtyard? Luna walked at a constant speed the entire time.
First solution.

![](https://cdn.mathpix.com/cropped/2024_05_30_1ae5e90785d026149547g-02.jpg?height=234&width=748&top_left_y=1119&top_left_x=263)

In her walk, Luna walked along the shorter side of the courtyard a total of 4 times, and it took her $(4 \cdot 15)$ seconds $=60$ seconds. 2 POINTS

Luna walked around the courtyard twice in 3 minutes and 20 seconds $=200$ seconds.

1 POINT

In her walk, Luna walked along the longer side of the courtyard for a total of (200 - 60) seconds $=140$ seconds.

1 POINT

Since she walked along the longer side of the courtyard a total of 4 times, then she walked along each longer side of the courtyard for $(140: 4)$ seconds $=35$ seconds.

##