One week, Isabelle bought 2 bags of apples and 3 bags of oranges. The next week, she bought 1 bag of apples and 2 bags of oranges. If a represents the cost of each bag of apples and r represents the cost of each bag of oranges, which expression could Isabelle use to calculate the difference between the amounts she spent each week?

Question

jhonyy9 · Answer

one week bought 2*a and 3*r
second week 1*a and 2*r 
so how you get the difference of these two weeks ?