Calculate the perimeter of the given shapes and solve a word problem about distance walked.

Length ($L$) = 9 cm  
Width ($W$) = 7 cm

$$
P = 2(9 \text{ cm} + 7 \text{ cm})
$$

$$
P = 2(16 \text{ cm})
$$
$$
P = 32 \text{ cm}
$$
The perimeter of the first shape is $\boxed{\text{32 cm}}$.

The outer sides are 4 cm (top), 3 cm (left), 4 cm (bottom), 5 cm (right slanted), and 5 cm (top slanted).

$$
P = 4 \text{ cm} + 3 \text{ cm} + 4 \text{ cm} + 5 \text{ cm} + 5 \text{ cm}
$$

$$
P = 21 \text{ cm}
$$
The perimeter of the second shape is $\boxed{\text{21 cm}}$.

Distance to campus = 2 km  
Distance back home = 2 km  
Daily distance = $2 \text{ km} + 2 \text{ km} = 4 \text{ km}$

Total distance = Daily distance $\times$ Number of days  
Total distance = $4 \text{ km/day} \times 5 \text{ days}$

Total distance = $20 \text{ km}$  
Joy walks a total distance of $\boxed{\text{20 km}}$.

Length ($L$) = 12 m  
Width ($W$) = 7 m

$$
P = 2(12 \text{ m} + 7 \text{ m})
$$

$$
P = 2(19 \text{ m})
$$
$$
P = 38 \text{ m}
$$
The perimeter of the garden is $\boxed{\text{38 m}}$.