Question

If 4 notebooks and 3 packages of pens cost $7.43 and 5 notebooks and 2 packages of pens cost $7.03, what is the cost of 1 notebook?

Answer 1

Let the cost of 1 notebook be X.

And cost of 1 package of pens be Y.

(Since 4 notebooks and 3 package of pens cost $7.43)

4X + 3Y = $7.43 ------(equation 1)

(Since 5 notebooks and 2 package of pens cost $7.03)

5X + 2Y= $7.03 -------(equation 2)

Now solving equation 1 and 2

Multiply equation 1 by 2 and multiply equation 2 by 3,we get

8X + 6Y = $14.86 ------equation 3 (equation 1 *2)

15X + 6Y = $21.09 -----equation 4 (equation 2 *3)

equation 4 - equation 3, we get

7X = 6.23

X= 6.23/7

X= 0.89

Hence,cost of 1 notebook is $0.89.