So in a gallon there is 4 quarts, and in 1 quart there are 2 pints and in 1 pint there are 2 cups.
So for the 1 quart of onion that would equal 4 cups. Then for the 4 pints of broth there would be 8 cups and then the 6 cups and 2 cups just stay the same. So if you add those number of cups up you would get 20 cups. Divide that by 4 to see how many bowls she would need.
The answer is she would need 5 bowls