Question

Maggie’s mom agrees to let Maggie buy small gifts for some of her friends. Each gift costs $4. Maggie’s mom gave her a budget of $19. When Maggie went online to order the gifts, she discovered there was a $7 shipping fee no matter how many gifts she bought. Use arithmetic (without variables) to determine how many gifts Maggie can buy. Record your steps. Write an algebraic equation to determine how many gifts Maggie can buy with $19, and solve your equation. Record your steps. Compare and contrast the two methods of solving the problem. 6-79.

Answer 1

Maggie can buy 3 gifts

Solution:

Total budget $19

Each gift costs $4

Shipping fee $7

a.  Total budget — Shipping fee = $19 - $7 = $12  

Maggie’s got $12 more

Each gift costs $4  

Number of gifts that Maggie can buy = $\frac{12}{4}$  =3  

b.   Let x represent the number of gifts.  

                      19 = 7 +4x

       Subtract -7 from both sides

             19 - 7= 7 + 4x - 7

            Now Simplify,

                   12 = 4x

         Divide both sides by 4

                   $\frac{12}{4} = \frac{4x}{4}$

                      x = 3