Official Solution:In August, an Olympic venue was selling two types of tickets, Regular and VIP, at different full prices. In September, both types of tickets went on sale and were sold at discounted prices. In September, how much more does a VIP ticket cost than a Regular ticket? This statement is clearly insufficient, since we need the difference in prices in September.
(1) In August, a VIP ticket cost $25 more than a Regular ticket.
(2) Both types of tickets were discounted by 20%.
This statement is also clearly insufficient.
(1) + (2) Given that a VIP ticket (V) cost $25 more than a Regular ticket (R) in August, we have \(V - R = 25\). Both tickets were discounted by 20%, so the prices in September would be \(0.8V\) and \(0.8R\). Therefore, the difference in September is \(0.8V - 0.8R = 0.8(V - R) = 0.8 * 25 = 20\). Sufficient.
Answer: C