Answer: Megan needs to buy 2 gallons of purple paint altogether for her room.
Explanation:
Since,
1 gallon = 4 quarts
Paint for the walls = 1 gallon
Paint for ceiling = 2 quarts
Paint for trim = 1 quart
Extra paint = 1 quart
Total paint required = 1 gallon + ( 2+1+1 quarts)
= 1 gallon + (4 quarts)
= 1 gallon + 1 gallon
= 2 gallons of paint in total.