The number of yellow markers is thrice the number of brown markers. The number of brown markers is 8 more than the number of red markers. The total number of markers is 122. The cost of each yellow marker is $3.30 and the cost of each red marker is $1.80. The total cost of all the markers is $357.40.

1. Find the number of red markers.
2. Find the cost of a brown marker.

(a)
Number of red markers = 1 u
Number of brown markers = 1 u + 8

Number of yellow markers
= 3(1 u + 8)
= 3 u + 24

Total of number of markers
= 1 u + 1 u + 8 + 3 u + 24
= 5 u + 32

5 u + 32 = 122
5 u = 122 - 32
5 u = 90

1 u = 90 ÷ 5 = 18

Number of red markers
= 1 u
= 18

(b)
Number of red markers = 18

Number of brown markers
=  18 + 8
= 26

Number of yellow markers
= 3 x 26
= 78

Cost of red markers 
= 18 x 1.80
= $32.40

Cost of yellow markers 
= 78 x 3.30
= $257.40

Cost of brown markers
= 357.40 - 257.40 - 32.40
= $67.60

Cost of 1 brown marker
= 67.60 ÷ 26
= $2.60

Answer(s) (a) 18; (b) $2.60