I need help understanding expressions!

Question

At the grocery store, Lindsay bought several pounds of strawberries. The strawberries cost $2.25 per pound. After she paid the cashier, she had $8.75 remaining. Write an expression with one variable to represent the amount of money Lindsay had before she bought the strawberries. Then, use your expression to find how much money Lindsay started with before buying 4 pounds of strawberries.

Answer 1

(price per pound)*(number of pounds)= how much she spent

(change after paying) = this is what remains after spending some of the money she started with 

So,

(price per pound)*(number of pounds)+(change after paying)=Total amount of money she had before she spent it

This can be written using the values given,

2.25*4+8.75=x 

⇒  x=$17.75

 

Hope this helps.