3. Variant 1.

In the apartment, there are four square rooms, which are marked as room №1, №2, №3, №4, and a corridor (№5). The perimeter of room №1 is 16 m, and the perimeter of room №2 is 24 m. What is the perimeter of the corridor (№5)? Give your answer in meters.

![](https://cdn.mathpix.com/cropped/2024_05_06_e52e9ad9ca4b338de450g-2.jpg?height=287&width=395&top_left_y=1583&top_left_x=819)
Answer: 40.

Solution. The side of room No.1 is $16: 4=4$ meters (we divide by 4 because a square has 4 equal sides), and the side of room No.2 is $24: 4=6$ meters. Then, the side of room No.3 is $6+4=10$ meters, so the side of room No.4 is $10+4=14$ meters. Therefore, the longer side of the corridor is $14+4=18$ meters, and the shorter side is $6-4=2$ meters. The perimeter of the corridor is $(2+18) \cdot 2=40$ meters.