That's the simplest it can go.
Answer : 58 square units.
Tip : break the shape down into shapes you can easily find the area of.
I found the area of the two squares on the bottom
They are identical and are both 2 units tall and two units long giving, giving an area of 4, and since there are two of them you can multiply the are by two giving you 8
Next found the area of the remaining shape which is just a rectangle that excludes the two bottom squares which is 10 units long and 5 units tall multiplying to 50
50+8=58
2 adults = 5.50 x 2 = 11
3 students = 4.25 x 3 = 12.75
Total = $23.75