The number of orange folders is thrice the number of blue folders. The number of blue folders is 6 more than the number of purple folders. The total number of folders is 139. The cost of each orange folder is $2.70 and the cost of each purple folder is $2.80. The total cost of all the folders is $363.10.
- Find the number of purple folders.
- Find the cost of a blue folder.
(a)
Number of purple folders = 1 u
Number of blue folders = 1 u + 6
Number of orange folders
= 3(1 u + 6)
= 3 u + 18
Total of number of folders
= 1 u + 1 u + 6 + 3 u + 18
= 5 u + 24
5 u + 24 = 139
5 u = 139 - 24
5 u = 115
1 u = 115 ÷ 5 = 23
Number of purple folders
= 1 u
= 23
(b)
Number of purple folders = 23
Number of blue folders
= 23 + 6
= 29
Number of orange folders
= 3 x 29
= 87
Cost of purple folders
= 23 x 2.80
= $64.40
Cost of orange folders
= 87 x 2.70
= $234.90
Cost of blue folders
= 363.10 - 234.90 - 64.40
= $63.80
Cost of 1 blue folder
= 63.80 ÷ 29
= $2.20
Answer(s) (a) 23; (b) $2.20
