Mary spent $92 on some notebooks, files and pencils. The number of notebooks she bought was ¹₂ the number of files. The number of pencils she bought was ³₄ the number of files. The ratio of the amount of money she spent on the notebooks, files and pencils was 8 : 6 : 9. The files were sold at 5 for $6. Find the price of 1 notebook.

Amount spent
Notebooks	Files	Pencils	Total
8 u	6 u	9 u	$92

Total amount that Mary spent on notebooks, files and pencils
= 8 u + 6 u + 9 u
= 23 u

23 u = 92

1 u = 92 ÷ 23 = 4

Amount that Mary spent on files
= 6 u
= 6 x 4
= $24

Number of sets of files of 5 bought
= 24 ÷ 6
= 4

Number of files that Mary bought
= 4 x 5
= 20

Number of items bought
Notebooks	Files	Pencils	Total
1x2	2x2
	4x1	3x1
2 p	4 p	3 p	9 p

The number of files bought is repeated.  Make the number of files bought is the same.  LCM of 2 and 4 is 4.

Number of files that Mary bought = 4 p

4 p = 20

1 p = 20 ÷ 4 = 5

Number of notebooks that Mary bought
= 2 p
= 2 x 5
= 10

Amount that Mary spent on notebooks
= 8 u
= 8 x 4
= $32

Price of 1 notebook
= 32 ÷ 10
= $3.20

Answer(s): $3.20