Answer:
Removing pennies and dimes from the bag
Explanation:
From the beginning, we have a 1 in 3 chance of drawing a quarter. If we were to add dimes and/or pennies to the bag, this would make us more likely to draw a dime or a penny, and less likely to draw a quarter. Proportionally, we want the most quarters in the bag to get the highest probability of drawing a quarter from the bag.