Final answer:
a) $24.50. To calculate the cost of Gina's dinner, you need to find 25% of the total bill. This is done by converting the percentage to a decimal and then multiplying it by the total bill. In this case, Gina's dinner cost $24.50.
Step-by-step explanation:
To find the cost of Gina's dinner, we need to calculate 25% of the total bill. First, convert 25% to a decimal by dividing it by 100: 25% = 0.25. Next, multiply the decimal by the total bill: 0.25 * $98 = $24.50.
Therefore, Gina's dinner cost $24.50.