Tammy spent $112 on some files, markers and staplers. The number of files she bought was ³₄ the number of markers. The number of staplers she bought was ¹₅ the number of markers. The ratio of the amount of money she spent on the files, markers and staplers was 9 : 5 : 2. The markers were sold at 4 for $7. Find the price of 1 file.

Amount spent
Files	Markers	Staplers	Total
9 u	5 u	2 u	$112

Total amount that Tammy spent on files, markers and staplers
= 9 u + 5 u + 2 u
= 16 u

16 u = 112

1 u = 112 ÷ 16 = 7

Amount that Tammy spent on markers
= 5 u
= 5 x 7
= $35

Number of sets of markers of 4 bought
= 35 ÷ 7
= 5

Number of markers that Tammy bought
= 5 x 4
= 20

Number of items bought
Files	Markers	Staplers	Total
3x5	4x5
	5x4	1x4
15 p	20 p	4 p	39 p

The number of markers bought is repeated.  Make the number of markers bought is the same.  LCM of 4 and 5 is 20.

Number of markers that Tammy bought = 20 p

20 p = 20

1 p = 20 ÷ 20 = 1

Number of files that Tammy bought
= 15 p
= 15 x 1
= 15

Amount that Tammy spent on files
= 9 u
= 9 x 7
= $63

Price of 1 file
= 63 ÷ 15
= $4.20

Answer(s): $4.20