Answer:
<em>The tip was </em><em>15% </em><em>of the meal.</em>
Step-by-step explanation:
The amount of tip that miss Holman gave is 90 cent or $0.90
The total cost of the meal is $6.00
Let the tip is x% of the total cost of $6, so the amount of tip is,

But as it given as $0.90, so



Therefore, miss Holman gave a generous 15% tip to the waitress for serving the meal.