6. Ms. Halpert wrote the table on the board and asked for her students to find the missing value.
Who found the correct missing value?
# OF CUPS
OF COFFEE
4
6
12
COST ($)
10.60
15.90
?
31.8
ERIN
I subtracted.
15.90 and 10.60,
then added
5.30 and 15.90,
so 9 cups of
coffee is
$21.20.
OSCAR
I divided 10.60
by 4 and found
1
cup of
coffee is $2.65,
so 9 cups of
coffee is
$23.85.