The number of yellow files is four times the number of brown files. The number of brown files is 8 more than the number of blue files. The total number of files is 118. The cost of each yellow file is $3.60 and the cost of each blue file is $1.90. The total cost of all the files is $364.90.
- Find the number of blue files.
- Find the cost of a brown file.
(a)
Number of blue files = 1 u
Number of brown files = 1 u + 8
Number of yellow files
= 4(1 u + 8)
= 4 u + 32
Total of number of files
= 1 u + 1 u + 8 + 4 u + 32
= 6 u + 40
6 u + 40 = 118
6 u = 118 - 40
6 u = 78
1 u = 78 ÷ 6 = 13
Number of blue files
= 1 u
= 13
(b)
Number of blue files = 13
Number of brown files
= 13 + 8
= 21
Number of yellow files
= 4 x 21
= 84
Cost of blue files
= 13 x 1.90
= $24.70
Cost of yellow files
= 84 x 3.60
= $302.40
Cost of brown files
= 364.90 - 302.40 - 24.70
= $37.80
Cost of 1 brown file
= 37.80 ÷ 21
= $1.80
Answer(s) (a) 13; (b) $1.80
