Problem 4. The area of a courtyard, which has the shape of a rectangle, is 10 ares. The length of one side is 25 meters. To fence the courtyard, a post needs to be placed every 5 meters. Calculate how many posts are needed to fence the courtyard and how many posts will be on each side?
Solution. Let $a=25 \text{ m}$ be the width, and $b=1000: 25=40 \text{ m}$ be the length of the yard. The perimeter of the yard is $L=2(25+40) \text{ m}=130 \text{ m}$. To fence the entire yard, $130: 5=26$ posts are needed. On the longer side, there are 9 posts, and on the shorter side, there are 6 posts.

## VI Department