To find the original price of each concert ticket without the discount, you can follow these steps:
1. Let's assume the original price of each ticket is represented by "x".
2. Since you and your 3 friends bought tickets, the total number of tickets is 4.
3. The total cost of the tickets after the $20 discount per ticket is applied can be calculated by subtracting $20 from the original price, which gives us "x - 20".
4. Now, multiply the discounted price by the total number of tickets to find the total amount spent: (x - 20) * 4.
5. According to the problem, the total amount spent is $420, so we can set up an equation: (x - 20) * 4 = 420.
6. To find the original price of each ticket, we need to solve this equation. Start by dividing both sides of the equation by 4: (x - 20) = 420 / 4.
7. Simplifying further, we have: x - 20 = 105.
8. Finally, add 20 to both sides of the equation to isolate the variable "x": x = 105 + 20.
9. Evaluating the equation, we find that x = 125.
Therefore, the original price of each concert ticket without the discount is 125.