Answer: the percentage discount given for the coupon is 37.5%
Step-by-step explanation:
Let x represent the discounted price.
There is then a service fee of 20% applied to the discounted price. It means that the value of the service fee is
20/100 × x = 0.2x
The price of the ticket would be
x + 0.2x = 1.2x
If the final amount paid for the tickets was $126, it means that
1.2x = 126
x = 126/1.2 = $105
The Concert tickets were originally priced at $168. With your coupon, the price became $105. Therefore, the amount taken off the original price is
168 - 105 = $63
Therefore, the percentage discount given for the coupon is
63/168 × 100 = 37.5%