Linda spent $42 on some notebooks, pens and files. The number of notebooks she bought was ¹₂ the number of pens. The number of files she bought was ³₅ the number of pens. The ratio of the amount of money she spent on the notebooks, pens and files was 7 : 6 : 8. The pens were sold at 5 for $6. Find the price of 1 notebook.

Amount spent
Notebooks	Pens	Files	Total
7 u	6 u	8 u	$42

Total amount that Linda spent on notebooks, pens and files
= 7 u + 6 u + 8 u
= 21 u

21 u = 42

1 u = 42 ÷ 21 = 2

Amount that Linda spent on pens
= 6 u
= 6 x 2
= $12

Number of sets of pens of 5 bought
= 12 ÷ 6
= 2

Number of pens that Linda bought
= 2 x 5
= 10

Number of items bought
Notebooks	Pens	Files	Total
1x5	2x5
	5x2	3x2
5 p	10 p	6 p	21 p

The number of pens bought is repeated.  Make the number of pens bought is the same.  LCM of 2 and 5 is 10.

Number of pens that Linda bought = 10 p

10 p = 10

1 p = 10 ÷ 10 = 1

Number of notebooks that Linda bought
= 5 p
= 5 x 1
= 5

Amount that Linda spent on notebooks
= 7 u
= 7 x 2
= $14

Price of 1 notebook
= 14 ÷ 5
= $2.80

Answer(s): $2.80