Question

A pencil cost $3.50 and a pen cost $6.70. Jessica bought M pens . She also bought four fewer pencils then pens. Write an algebraic expression for the total amount she spent.

Answer 1

Ok so Jessica bought M pens, which cost $6.70 each.
She also bought 4 fewer pencils than pens, or (M-4) pencils, at $3.50 each.

So in total, she spent:
6.7M + 3.5(M-4)
= 6.7M + 3.5M - 14
= 10.2M -14

So she spent $(10M - 14) on pens and pencils.

Hope this helped