The number of orange staplers is thrice the number of red staplers. The number of red staplers is 5 more than the number of green staplers. The total number of staplers is 130. The cost of each orange stapler is $2.90 and the cost of each green stapler is $2.80. The total cost of all the staplers is $328.90.

1. Find the number of green staplers.
2. Find the cost of a red stapler.

(a)
Number of green staplers = 1 u
Number of red staplers = 1 u + 5

Number of orange staplers
= 3(1 u + 5)
= 3 u + 15

Total of number of staplers
= 1 u + 1 u + 5 + 3 u + 15
= 5 u + 20

5 u + 20 = 130
5 u = 130 - 20
5 u = 110

1 u = 110 ÷ 5 = 22

Number of green staplers
= 1 u
= 22

(b)
Number of green staplers = 22

Number of red staplers
=  22 + 5
= 27

Number of orange staplers
= 3 x 27
= 81

Cost of green staplers 
= 22 x 2.80
= $61.60

Cost of orange staplers 
= 81 x 2.90
= $234.90

Cost of red staplers
= 328.90 - 234.90 - 61.60
= $32.40

Cost of 1 red stapler
= 32.40 ÷ 27
= $1.20

Answer(s) (a) 22; (b) $1.20