Answer:
The price of the television before taxes is $420
Step-by-step explanation:
* Lets explain how to solve the problem
- The purchased price = cost price +  taxes
- A new television set was recently purchased for the common room
  in a residence hall for $436.80
- This price including tax
- The tax rate is 4%
- We need to find the price of the television before taxes
* <em>Lets solve the problem</em>
- Assume that the price of the television before tax is 100%
∵ The tax rate is 4%
∵ The price after tax = price before tax + tax
∵ The price before tax = 100%
∴ The price after tax  = 100% + 4% = 104%
∵ 104% equivalent to $436.80
∴ 100   ⇒   ?
   104   ⇒   436.80
- <em>By using cross multiplication</em>
∴ ? = 
∴ The price of the television before taxes is $420