Question

Mary opened a 1-qt carton of milk. She drank 1 c of it. How many cups of milk were left?

Answer 1

Hint: This question is a word problem that can be solved by giving attention to the important details in the question. To find out the remaining cups of milk left, we simply subtract the original amount of milk left in the cup by the amount she consumed.

Complete step by step solution:
The question states that Mary opened a 1-qt carton of milk. This gives us the quantity of milk initially or the original amount of milk. 1-qt represents 1 quart. In 1 quart, there are 4 cups. So, in the 1-quart carton of milk that Mary opened, there were 4 cups of milk.
No. of cups of milk in the 1-quart carton of milk before consumption = 4 …… (1)
Next, it is given that she consumes or drinks 1 cup of milk. Therefore,
No. of cups of milk Mary consumed from the 1-quart carton of milk = 1 …… (2)
To find out the amount of milk left in the 1-quart carton, all we need to do is to just subtract the amount of milk originally present in the carton and the amount Mary consumes.
No. of cups of milk left in the carton = No. of cups of milk in the 1-quart carton of milk before consumption - No. of cups of milk Mary consumed from the 1-quart carton of milk ……(3)
$\Rightarrow 4-1$ cups
$\Rightarrow 3$ cups
Therefore, there were 3 cups of milk after Mary consumed her 1 cup of milk.
Hence the answer is 3 cups.

Note: We need to take care while converting from quart to the number of cups. It should be remembered that 1-quart is the same as 2 pints which is the same as 4 cups. It is a unit of liquid capacity equal to a quarter of a gallon.