The number of red files is twice the number of green files. The number of green files is 5 more than the number of yellow files. The total number of files is 131. The cost of each red file is $3.20 and the cost of each yellow file is $2.60. The total cost of all the files is $347.40.
- Find the number of yellow files.
- Find the cost of a green file.
(a)
Number of yellow files = 1 u
Number of green files = 1 u + 5
Number of red files
= 2(1 u + 5)
= 2 u + 10
Total of number of files
= 1 u + 1 u + 5 + 2 u + 10
= 4 u + 15
4 u + 15 = 131
4 u = 131 - 15
4 u = 116
1 u = 116 ÷ 4 = 29
Number of yellow files
= 1 u
= 29
(b)
Number of yellow files = 29
Number of green files
= 29 + 5
= 34
Number of red files
= 2 x 34
= 68
Cost of yellow files
= 29 x 2.60
= $75.40
Cost of red files
= 68 x 3.20
= $217.60
Cost of green files
= 347.40 - 217.60 - 75.40
= $54.40
Cost of 1 green file
= 54.40 ÷ 34
= $1.60
Answer(s) (a) 29; (b) $1.60
