Mark uses 1 pt 9 fl oz and then 2 pt 10 fl oz from a container of film developer that holds 3 qt . How much of the developer remains?
19 ounces?
Be careful here: the Imperial and U.S. Customary fluid ounces are different. In the Imperial system there are 20 fl oz in a pint, whereas in the U.S. system there are 16 fl oz in a pint. There are two pints in a quart in both systems. Which side of the Atlantic are you from?
To find out how much of the developer remains, we need to subtract the amount Mark used from the total amount in the container.
First, let's convert all the measurements to a common unit, such as fluid ounces (fl oz) or pints (pt).
We can convert 3 qt to pints by multiplying it by 2, as there are 2 pints in a quart:
3 qt = 3 * 2 pt = 6 pt
Now, let's convert the amounts Mark used to pints as well:
1 pt 9 fl oz = 1 pt + 9/16 pt (since there are 16 fl oz in a pint)
= 1.5625 pt
2 pt 10 fl oz = 2 pt + 10/16 pt
= 2.625 pt
Now we can subtract the amount Mark used from the total amount in the container:
Remaining amount = Total amount - Amount used
= 6 pt - (1.5625 pt + 2.625 pt)
= 6 pt - 4.1875 pt (add the quantities in parentheses)
= 1.8125 pt
Therefore, there are 1 pt 13.5 fl oz (or approximately 1 pint 14 fl oz) of film developer remaining in the container.