The number of red folders is twice the number of brown folders. The number of brown folders is 8 more than the number of purple folders. The total number of folders is 140. The cost of each red folder is $4.20 and the cost of each purple folder is $3.30. The total cost of all the folders is $495.30.
- Find the number of purple folders.
- Find the cost of a brown folder.
(a)
Number of purple folders = 1 u
Number of brown folders = 1 u + 8
Number of red folders
= 2(1 u + 8)
= 2 u + 16
Total of number of folders
= 1 u + 1 u + 8 + 2 u + 16
= 4 u + 24
4 u + 24 = 140
4 u = 140 - 24
4 u = 116
1 u = 116 ÷ 4 = 29
Number of purple folders
= 1 u
= 29
(b)
Number of purple folders = 29
Number of brown folders
= 29 + 8
= 37
Number of red folders
= 2 x 37
= 74
Cost of purple folders
= 29 x 3.30
= $95.70
Cost of red folders
= 74 x 4.20
= $310.80
Cost of brown folders
= 495.30 - 310.80 - 95.70
= $88.80
Cost of 1 brown folder
= 88.80 ÷ 37
= $2.40
Answer(s) (a) 29; (b) $2.40
