I think that inches would be most common for height but centimeters and feet could also be used.
Answer:
Equation is
where
denotes number of cups of orange juice needed by Sam.

Step-by-step explanation:
Let
denotes number of cups of orange juice needed by Sam.
Number of cups needed to make punch 
Number of cups with Sam 
Therefore,

Times 4 because, 5 times 4 is 20, 20 times 4 is 80 and so on.
Answer: 3 (
x
+
7
)
Step-by-step explanation: