Patrick T. answered 11/27/21
Tutor Specializing in French & Math (up to college Pre-Calculus)
Hello Aja,
Let s be the number of boxes of standard strawberries
Let d be the number of boxes of deluxe strawberries
This sentence "In one day the stand sold 135 boxes of strawberries for a total of $1,245" contains the info we need to set up the 2 equations:
135 boxes of strawberries sold -----> s + d = 135 (#1)
strawberries sold for a total of $1,245 -------> 7s + 12d = 1245 (#2)
Multiply equation #1 by -7 so you can add it to the equation #2 and eliminate s:
-7s - 7d = -945
7s + 12d = 1245
Adding both equations ---> 5d = 300
Divide by 5 ---> d = 60, meaning 60 boxes of deluxe strawberries were sold.
Recall 135 total boxes were sold. 60 of those were deluxe boxes, so you can figure out how many boxes of standard strawberries were sold.