Question

Cindy plans to shop for her school supplies and wants to know how much money she would need to spend. from her friend she knows that buying 4 notebooks and 3 binders would cost $23.5, and 7 notebooks and 6 binders would cost $44.5. Cindy plans to buy 5 notebooks and 2 binders. How much would that cost?

Answer 1

Let the cost of 1 notebook be x and the cost of 1 binder be y.

4 notebooks and 3 binders would cost 23.5

Therefore, 4x + 3y = 23.5     (1)

7 notebooks and 6 binders would cost 44.5

Therefore, 7x + 6y = 44.5     (2)

Multiply the first equation by 2.

8x + 6y = 47     (3)

(3) - (2) gives

x = 2.5

Substitute the value of x in (1), we get,

4(2.5) + 3y = 23.5

10 + 3y = 23.5

3y = 23.5 - 10

3y = 13.5

y = 13.5/3

y = 4.5

Hence, cost of 5 notebooks and 3 binders is:

5x + 3y = 5(2.5) + 3(4.5)

           = 12.5 + 13.5

           = 26

Hence, cost of 5 notebooks and 3 binders is $26.