The number of yellow files is thrice the number of red files. The number of red files is 8 more than the number of green files. The total number of files is 112. The cost of each yellow file is $3.20 and the cost of each green file is $1.80. The total cost of all the files is $285.60.
- Find the number of green files.
- Find the cost of a red file.
(a)
Number of green files = 1 u
Number of red files = 1 u + 8
Number of yellow files
= 3(1 u + 8)
= 3 u + 24
Total of number of files
= 1 u + 1 u + 8 + 3 u + 24
= 5 u + 32
5 u + 32 = 112
5 u = 112 - 32
5 u = 80
1 u = 80 ÷ 5 = 16
Number of green files
= 1 u
= 16
(b)
Number of green files = 16
Number of red files
= 16 + 8
= 24
Number of yellow files
= 3 x 24
= 72
Cost of green files
= 16 x 1.80
= $28.80
Cost of yellow files
= 72 x 3.20
= $230.40
Cost of red files
= 285.60 - 230.40 - 28.80
= $26.40
Cost of 1 red file
= 26.40 ÷ 24
= $1.10
Answer(s) (a) 16; (b) $1.10
