Irene spent $153 on some staplers, files and pens. The number of staplers she bought was ²₃ the number of files. The number of pens she bought was ¹₂ the number of files. The ratio of the amount of money she spent on the staplers, files and pens was 3 : 5 : 9. The files were sold at 2 for $5. Find the price of 1 stapler.

Amount spent
Staplers	Files	Pens	Total
3 u	5 u	9 u	$153

Total amount that Irene spent on staplers, files and pens
= 3 u + 5 u + 9 u
= 17 u

17 u = 153

1 u = 153 ÷ 17 = 9

Amount that Irene spent on files
= 5 u
= 5 x 9
= $45

Number of sets of files of 2 bought
= 45 ÷ 5
= 9

Number of files that Irene bought
= 9 x 2
= 18

Number of items bought
Staplers	Files	Pens	Total
2x2	3x2
	2x3	1x3
4 p	6 p	3 p	13 p

The number of files bought is repeated.  Make the number of files bought is the same.  LCM of 3 and 2 is 6.

Number of files that Irene bought = 6 p

6 p = 18

1 p = 18 ÷ 6 = 3

Number of staplers that Irene bought
= 4 p
= 4 x 3
= 12

Amount that Irene spent on staplers
= 3 u
= 3 x 9
= $27

Price of 1 stapler
= 27 ÷ 12
= $2.25

Answer(s): $2.25