Joan made 1 1/2 gallons of punch. She used 2 pints of lemonade and 3 quarts of ginger ale. The rest of the punch was orange juice. How many quarts of orange juice did Joan use?

(Having used the metric system for the last 50 years, I had to recall all that gallon, pints and quart stuff)

change all to pints
3quarts = 6 pints
1 1/2 gallons = 12 pints

let the amount of orange juice she used be x pints
2 + 6 + x = 12
x = 4 pints

she used 4 pints of orange juice or 2 quarts of orange juice.

(how easy this would have been in litres)

To find out how many quarts of orange juice Joan used, we need to first determine the total amount of liquid in the punch.

1 1/2 gallons can be converted to quarts by multiplying it by 4 since there are 4 quarts in a gallon.

1 1/2 gallons * 4 quarts/gallon = 6 quarts

Now, we need to subtract the amount of lemonade (2 pints) and ginger ale (3 quarts) from the total amount of punch (6 quarts) to find out how much orange juice was used.

First, let's convert pints to quarts by dividing by 2 since there are 2 pints in a quart.

2 pints / 2 quarts/pint = 1 quart

Then, we add the amount of ginger ale to the converted lemonade:

3 quarts (ginger ale) + 1 quart (converted lemonade) = 4 quarts

Finally, subtracting the sum from the total amount of punch:

6 quarts - 4 quarts = 2 quarts

Therefore, Joan used 2 quarts of orange juice in her punch.