Step-by-step explanation:
The dimensions of the cuboid are 5 cm, 7 cm and 9 cm.
The formula for the surface area of the cuboid is as follows :

We have,
b = 9 cm, l = 7 cm and h = 5 cm
So,

Jamie forgets to multiply 143 by 2 as the formula for surface area contains 2 as well.
Given:
Joining fee = $28
Fee of each event = $4
To find:
Total cost for someone to attend 4 events.
Solution:
Let the number of events be x and total fee be y.
Fee for 1 event = $4
Fee for x events = $4x
Joining fee remains constant. So, the total fee is

Substitute x=4 in this equation.



Therefore, total cost of 4 events is $44.