Question

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?

Answer 1

It should be   (2a+3r)-(1a+2r).

Answer 2

The expression (a+r) could be used by Isabelle to calculate the difference between the amounts she spent each week.

Explanation:

Given

a= the cost of each bag of apples

r=the cost of each bag of oranges

Therefore amount spent by Isabelle in the first week,
`P_(w1)=2a+3r`

and amount spent by Isabelle in the next week,
`P_(w2)=a+2r`

Thus difference between the amount she spent is given by

`P=P_(w1)-P_(w2)=(2a+3r)-(a+2r)`

=>
`P=(2a+3r)-(a+2r)=(a+r)`

Thus the expression (a+r) could be used by Isabelle to calculate the difference between the amounts she spent each week.