The number of blue folders is thrice the number of brown folders. The number of brown folders is 9 more than the number of red folders. The total number of folders is 106. The cost of each blue folder is $3.50 and the cost of each red folder is $1.90. The total cost of all the folders is $309.50.
- Find the number of red folders.
- Find the cost of a brown folder.
(a)
Number of red folders = 1 u
Number of brown folders = 1 u + 9
Number of blue folders
= 3(1 u + 9)
= 3 u + 27
Total of number of folders
= 1 u + 1 u + 9 + 3 u + 27
= 5 u + 36
5 u + 36 = 106
5 u = 106 - 36
5 u = 70
1 u = 70 ÷ 5 = 14
Number of red folders
= 1 u
= 14
(b)
Number of red folders = 14
Number of brown folders
= 14 + 9
= 23
Number of blue folders
= 3 x 23
= 69
Cost of red folders
= 14 x 1.90
= $26.60
Cost of blue folders
= 69 x 3.50
= $241.50
Cost of brown folders
= 309.50 - 241.50 - 26.60
= $41.40
Cost of 1 brown folder
= 41.40 ÷ 23
= $1.80
Answer(s) (a) 14; (b) $1.80
